View Source AWS.KMS (aws-elixir v0.13.3)
Key Management Service
Key Management Service (KMS) is an encryption and key management web service.
This guide describes the KMS operations that you can call programmatically. For general information about KMS, see the Key Management Service Developer Guide .
KMS has replaced the term customer master key (CMK) with KMS key and KMS key. The concept has not changed. To prevent breaking changes, KMS is keeping some variations of this term.
Amazon Web Services provides SDKs that consist of libraries and sample code for various programming languages and platforms (Java, Ruby, .Net, macOS, Android, etc.). The SDKs provide a convenient way to create programmatic access to KMS and other Amazon Web Services services. For example, the SDKs take care of tasks such as signing requests (see below), managing errors, and retrying requests automatically. For more information about the Amazon Web Services SDKs, including how to download and install them, see Tools for Amazon Web Services.
We recommend that you use the Amazon Web Services SDKs to make programmatic API calls to KMS.
If you need to use FIPS 140-2 validated cryptographic modules when communicating with Amazon Web Services, use the FIPS endpoint in your preferred Amazon Web Services Region. For more information about the available FIPS endpoints, see Service endpoints in the Key Management Service topic of the Amazon Web Services General Reference.
All KMS API calls must be signed and be transmitted using Transport Layer Security (TLS). KMS recommends you always use the latest supported TLS version. Clients must also support cipher suites with Perfect Forward Secrecy (PFS) such as Ephemeral Diffie-Hellman (DHE) or Elliptic Curve Ephemeral Diffie-Hellman (ECDHE). Most modern systems such as Java 7 and later support these modes.
signing-requests
Signing Requests
Requests must be signed using an access key ID and a secret access key. We strongly recommend that you do not use your Amazon Web Services account root access key ID and secret access key for everyday work. You can use the access key ID and secret access key for an IAM user or you can use the Security Token Service (STS) to generate temporary security credentials and use those to sign requests.
All KMS requests must be signed with Signature Version 4.
logging-api-requests
Logging API Requests
KMS supports CloudTrail, a service that logs Amazon Web Services API calls and related events for your Amazon Web Services account and delivers them to an Amazon S3 bucket that you specify. By using the information collected by CloudTrail, you can determine what requests were made to KMS, who made the request, when it was made, and so on. To learn more about CloudTrail, including how to turn it on and find your log files, see the CloudTrail User Guide.
additional-resources
Additional Resources
For more information about credentials and request signing, see the following:
- This topic provides general information about the types of credentials used to access Amazon Web Services.
- This section of the IAM User Guide describes how to create and use temporary security credentials.
- This set of topics walks you through the process of signing a request using an access key ID and a secret access key.
commonly-used-api-operations
Commonly Used API Operations
Of the API operations discussed in this guide, the following will prove the most useful for most applications. You will likely perform operations other than these, such as creating keys and assigning policies, by using the console.
Encrypt
Decrypt
GenerateDataKey
GenerateDataKeyWithoutPlaintext
Link to this section Summary
Functions
Cancels the deletion of a KMS key.
Connects or reconnects a custom key store to its backing key store.
Creates a friendly name for a KMS key.
Creates a custom key store backed by a key store that you own and manage.
Adds a grant to a KMS key.
Creates a unique customer managed KMS key in your Amazon Web Services account and Region.
Decrypts ciphertext that was encrypted by a KMS key using any of the following operations
Deletes the specified alias.
Deletes key material that you previously imported.
Gets information about custom key stores in the account and Region.
Provides detailed information about a KMS key.
Sets the state of a KMS key to disabled.
Disables automatic rotation of the key material of the specified symmetric encryption KMS key.
Disconnects the custom key store from its backing key store.
Sets the key state of a KMS key to enabled.
Enables automatic rotation of the key material of the specified symmetric encryption KMS key.
Encrypts plaintext of up to 4,096 bytes using a KMS key.
Returns a unique symmetric data key for use outside of KMS.
Returns a unique asymmetric data key pair for use outside of KMS.
Returns a unique asymmetric data key pair for use outside of KMS.
Returns a unique symmetric data key for use outside of KMS.
Generates a hash-based message authentication code (HMAC) for a message using an HMAC KMS key and a MAC algorithm that the key supports.
Returns a random byte string that is cryptographically secure.
Gets a key policy attached to the specified KMS key.
Gets a Boolean value that indicates whether automatic rotation of the key material is enabled for the specified KMS key.
Returns the items you need to import key material into a symmetric encryption KMS key.
Returns the public key of an asymmetric KMS key.
Imports key material into an existing symmetric encryption KMS key that was created without key material.
Gets a list of aliases in the caller's Amazon Web Services account and region.
Gets a list of all grants for the specified KMS key.
Gets the names of the key policies that are attached to a KMS key.
Gets a list of all KMS keys in the caller's Amazon Web Services account and Region.
Returns all tags on the specified KMS key.
Returns information about all grants in the Amazon Web Services account and Region that have the specified retiring principal.
Attaches a key policy to the specified KMS key.
Decrypts ciphertext and then reencrypts it entirely within KMS.
Replicates a multi-Region key into the specified Region.
Deletes a grant.
Deletes the specified grant.
Schedules the deletion of a KMS key.
Creates a digital signature for a message or message digest by using the private key in an asymmetric signing KMS key.
Adds or edits tags on a customer managed key.
Deletes tags from a customer managed key.
Associates an existing KMS alias with a different KMS key.
Changes the properties of a custom key store.
Updates the description of a KMS key.
Changes the primary key of a multi-Region key.
Verifies a digital signature that was generated by the Sign
operation.
Verifies the hash-based message authentication code (HMAC) for a specified message, HMAC KMS key, and MAC algorithm.
Link to this section Functions
Cancels the deletion of a KMS key.
When this operation succeeds, the key state of the KMS key is Disabled
. To
enable the KMS key, use EnableKey
.
For more information about scheduling and canceling deletion of a KMS key, see Deleting KMS keys in the Key Management Service Developer Guide.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:CancelKeyDeletion (key policy)
Related operations: ScheduleKeyDeletion
Connects or reconnects a custom key store to its backing key store.
For an CloudHSM key store, ConnectCustomKeyStore
connects the key store to its
associated CloudHSM cluster. For an external key store, ConnectCustomKeyStore
connects the key store to the external key store proxy that communicates with
your external key manager.
The custom key store must be connected before you can create KMS keys in the key store or use the KMS keys it contains. You can disconnect and reconnect a custom key store at any time.
The connection process for a custom key store can take an extended amount of
time to complete. This operation starts the connection process, but it does not
wait for it to complete. When it succeeds, this operation quickly returns an
HTTP 200 response and a JSON object with no properties. However, this response
does not indicate that the custom key store is connected. To get the connection
state of the custom key store, use the DescribeCustomKeyStores
operation.
This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.
The ConnectCustomKeyStore
operation might fail for various reasons. To find
the reason, use the DescribeCustomKeyStores
operation and see the
ConnectionErrorCode
in the response. For help interpreting the
ConnectionErrorCode
, see CustomKeyStoresListEntry
.
To fix the failure, use the DisconnectCustomKeyStore
operation to disconnect
the custom key store, correct the error, use the UpdateCustomKeyStore
operation if necessary, and then use ConnectCustomKeyStore
again.
cloudhsm-key-store
CloudHSM key store
During the connection process for an CloudHSM key store, KMS finds the CloudHSM
cluster that is associated with the custom key store, creates the connection
infrastructure, connects to the cluster, logs into the CloudHSM client as the
kmsuser
CU, and rotates its password.
To connect an CloudHSM key store, its associated CloudHSM cluster must have at
least one active HSM. To get the number of active HSMs in a cluster, use the
DescribeClusters operation. To add HSMs to the cluster, use the
CreateHsm
operation. Also, the kmsuser
crypto user
(CU) must not be logged into the cluster. This prevents KMS from using this
account to log in.
If you are having trouble connecting or disconnecting a CloudHSM key store, see Troubleshooting an CloudHSM key store in the Key Management Service Developer Guide.
external-key-store
External key store
When you connect an external key store that uses public endpoint connectivity, KMS tests its ability to communicate with your external key manager by sending a request via the external key store proxy.
When you connect to an external key store that uses VPC endpoint service connectivity, KMS establishes the networking elements that it needs to communicate with your external key manager via the external key store proxy. This includes creating an interface endpoint to the VPC endpoint service and a private hosted zone for traffic between KMS and the VPC endpoint service.
To connect an external key store, KMS must be able to connect to the external key store proxy, the external key store proxy must be able to communicate with your external key manager, and the external key manager must be available for cryptographic operations.
If you are having trouble connecting or disconnecting an external key store, see Troubleshooting an external key store in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.
Required permissions: kms:ConnectCustomKeyStore (IAM policy)
related-operations
Related operations
CreateCustomKeyStore
DeleteCustomKeyStore
DescribeCustomKeyStores
DisconnectCustomKeyStore
UpdateCustomKeyStore
Creates a friendly name for a KMS key.
Adding, deleting, or updating an alias can allow or deny permission to the KMS key. For details, see ABAC for KMS in the Key Management Service Developer Guide.
You can use an alias to identify a KMS key in the KMS console, in the
DescribeKey
operation and in cryptographic operations,
such as Encrypt
and GenerateDataKey
. You can also change the KMS key that's
associated with the alias (UpdateAlias
) or delete the alias (DeleteAlias
) at
any time. These operations don't affect the underlying KMS key.
You can associate the alias with any customer managed key in the same Amazon Web Services Region. Each alias is associated with only one KMS key at a time, but a KMS key can have multiple aliases. A valid KMS key is required. You can't create an alias without a KMS key.
The alias must be unique in the account and Region, but you can have aliases with the same name in different Regions. For detailed information about aliases, see Using aliases in the Key Management Service Developer Guide.
This operation does not return a response. To get the alias that you created,
use the ListAliases
operation.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on an alias in a different Amazon Web Services account.
required-permissions
Required permissions
* kms:CreateAlias on the alias (IAM policy).
* kms:CreateAlias on the KMS key (key policy).
For details, see Controlling access to aliases in the Key Management Service Developer Guide.
related-operations
Related operations:
DeleteAlias
ListAliases
UpdateAlias
Creates a custom key store backed by a key store that you own and manage.
When you use a KMS key in a custom key store for a cryptographic operation, the cryptographic operation is actually performed in your key store using your keys. KMS supports CloudHSM key stores backed by an CloudHSM cluster and external key stores backed by an external key store proxy and external key manager outside of Amazon Web Services.
This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.
Before you create the custom key store, the required elements must be in place and operational. We recommend that you use the test tools that KMS provides to verify the configuration your external key store proxy. For details about the required elements and verification tests, see Assemble the prerequisites (for CloudHSM key stores) or Assemble the prerequisites (for external key stores) in the Key Management Service Developer Guide.
To create a custom key store, use the following parameters.
To create an CloudHSM key store, specify the
CustomKeyStoreName
,CloudHsmClusterId
,KeyStorePassword
, andTrustAnchorCertificate
. TheCustomKeyStoreType
parameter is optional for CloudHSM key stores. If you include it, set it to the default value,AWS_CLOUDHSM
. For help with failures, see Troubleshooting an CloudHSM key store in the Key Management Service Developer Guide.To create an external key store, specify the
CustomKeyStoreName
and aCustomKeyStoreType
ofEXTERNAL_KEY_STORE
. Also, specify values forXksProxyConnectivity
,XksProxyAuthenticationCredential
,XksProxyUriEndpoint
, andXksProxyUriPath
. If yourXksProxyConnectivity
value isVPC_ENDPOINT_SERVICE
, specify theXksProxyVpcEndpointServiceName
parameter. For help with failures, see Troubleshooting an external key store in the Key Management Service Developer Guide.
For external key stores:
Some external key managers provide a simpler method for creating an external key store. For details, see your external key manager documentation.
When creating an external key store in the KMS console, you can upload a
JSON-based proxy configuration file with the desired values. You cannot use a
proxy configuration with the CreateCustomKeyStore
operation. However, you can
use the values in the file to help you determine the correct values for the
CreateCustomKeyStore
parameters.
When the operation completes successfully, it returns the ID of the new custom
key store. Before you can use your new custom key store, you need to use the
ConnectCustomKeyStore
operation to connect a new CloudHSM key store to its
CloudHSM cluster, or to connect a new external key store to the external key
store proxy for your external key manager. Even if you are not going to use your
custom key store immediately, you might want to connect it to verify that all
settings are correct and then disconnect it until you are ready to use it.
For help with failures, see Troubleshooting a custom key store in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.
Required permissions: kms:CreateCustomKeyStore (IAM policy).
related-operations
Related operations:
ConnectCustomKeyStore
DeleteCustomKeyStore
DescribeCustomKeyStores
DisconnectCustomKeyStore
UpdateCustomKeyStore
Adds a grant to a KMS key.
A grant is a policy instrument that allows Amazon Web Services principals to
use KMS keys in cryptographic operations. It also can allow them to view a KMS
key (DescribeKey
) and create and manage grants. When authorizing access to a
KMS key, grants are considered along with key policies and IAM policies. Grants
are often used for temporary permissions because you can create one, use its
permissions, and delete it without changing your key policies or IAM policies.
For detailed information about grants, including grant terminology, see Grants in KMS in the Key Management Service Developer Guide . For examples of working with grants in several programming languages, see Programming grants.
The CreateGrant
operation returns a GrantToken
and a GrantId
.
- When you create, retire, or revoke a grant, there might be a brief delay, usually less than five minutes, until the grant is available throughout KMS. This state is known as eventual consistency. Once the grant has achieved eventual consistency, the grantee principal can use the permissions in the grant without identifying the grant.
However, to use the permissions in the grant immediately, use the GrantToken
that CreateGrant
returns. For details, see Using a grant token
in the Key Management Service Developer Guide .
- The
CreateGrant
operation also returns aGrantId
. You can use theGrantId
and a key identifier to identify the grant in theRetireGrant
andRevokeGrant
operations. To find the grant ID, use theListGrants
orListRetirableGrants
operations.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation on a KMS key in a
different Amazon Web Services account, specify the key ARN in the value of the
KeyId
parameter.
Required permissions: kms:CreateGrant (key policy)
related-operations
Related operations:
ListGrants
ListRetirableGrants
RetireGrant
RevokeGrant
Creates a unique customer managed KMS key in your Amazon Web Services account and Region.
You can use a KMS key in cryptographic operations, such as encryption and signing. Some Amazon Web Services services let you use KMS keys that you create and manage to protect your service resources.
A KMS key is a logical representation of a cryptographic key. In addition to the key material used in cryptographic operations, a KMS key includes metadata, such as the key ID, key policy, creation date, description, and key state. For details, see Managing keys in the Key Management Service Developer Guide
Use the parameters of CreateKey
to specify the type of KMS key, the source of
its key material, its key policy, description, tags, and other properties.
KMS has replaced the term customer master key (CMK) with KMS key and KMS key. The concept has not changed. To prevent breaking changes, KMS is keeping some variations of this term.
To create different types of KMS keys, use the following guidance:
definitions
Definitions
symmetric-encryption-kms-key
Symmetric encryption KMS key
By default, CreateKey
creates a symmetric encryption KMS key with key material
that KMS generates. This is the basic and most widely used type of KMS key, and
provides the best performance.
To create a symmetric encryption KMS key, you don't need to specify any
parameters. The default value for KeySpec
, SYMMETRIC_DEFAULT
, the default
value for KeyUsage
, ENCRYPT_DECRYPT
, and the default value for Origin
,
AWS_KMS
, create a symmetric encryption KMS key with KMS key material.
If you need a key for basic encryption and decryption or you are creating a KMS
key to protect your resources in an Amazon Web Services service, create a
symmetric encryption KMS key. The key material in a symmetric encryption key
never leaves KMS unencrypted. You can use a symmetric encryption KMS key to
encrypt and decrypt data up to 4,096 bytes, but they are typically used to
generate data keys and data keys pairs. For details, see GenerateDataKey
and
GenerateDataKeyPair
.
asymmetric-kms-keys
Asymmetric KMS keys
To create an asymmetric KMS key, use the KeySpec
parameter to specify the type
of key material in the KMS key. Then, use the KeyUsage
parameter to determine
whether the KMS key will be used to encrypt and decrypt or sign and verify. You
can't change these properties after the KMS key is created.
Asymmetric KMS keys contain an RSA key pair, Elliptic Curve (ECC) key pair, or
an SM2 key pair (China Regions only). The private key in an asymmetric KMS key
never leaves KMS unencrypted. However, you can use the GetPublicKey
operation
to download the public key so it can be used outside of KMS. KMS keys with RSA
or SM2 key pairs can be used to encrypt or decrypt data or sign and verify
messages (but not both). KMS keys with ECC key pairs can be used only to sign
and verify messages. For information about asymmetric KMS keys, see Asymmetric KMS
keys
in the Key Management Service Developer Guide.
hmac-kms-key
HMAC KMS key
To create an HMAC KMS key, set the KeySpec
parameter to a key spec value for
HMAC KMS keys. Then set the KeyUsage
parameter to GENERATE_VERIFY_MAC
. You
must set the key usage even though GENERATE_VERIFY_MAC
is the only valid key
usage value for HMAC KMS keys. You can't change these properties after the KMS
key is created.
HMAC KMS keys are symmetric keys that never leave KMS unencrypted. You can use
HMAC keys to generate (GenerateMac
) and verify (VerifyMac
) HMAC codes for
messages up to 4096 bytes.
HMAC KMS keys are not supported in all Amazon Web Services Regions. If you try
to create an HMAC KMS key in an Amazon Web Services Region in which HMAC keys
are not supported, the CreateKey
operation returns an
UnsupportedOperationException
. For a list of Regions in which HMAC KMS keys
are supported, see HMAC keys in KMS in the
Key Management Service Developer Guide.
multi-region-primary-keys
Multi-Region primary keys
imported-key-material
Imported key material
To create a multi-Region primary key in the local Amazon Web Services Region,
use the MultiRegion
parameter with a value of True
. To create a multi-Region
replica key, that is, a KMS key with the same key ID and key material as a
primary key, but in a different Amazon Web Services Region, use the
ReplicateKey
operation. To change a replica key to a primary key, and its
primary key to a replica key, use the UpdatePrimaryRegion
operation.
You can create multi-Region KMS keys for all supported KMS key types: symmetric encryption KMS keys, HMAC KMS keys, asymmetric encryption KMS keys, and asymmetric signing KMS keys. You can also create multi-Region keys with imported key material. However, you can't create multi-Region keys in a custom key store.
This operation supports multi-Region keys, an KMS feature that lets you create multiple interoperable KMS keys in different Amazon Web Services Regions. Because these KMS keys have the same key ID, key material, and other metadata, you can use them interchangeably to encrypt data in one Amazon Web Services Region and decrypt it in a different Amazon Web Services Region without re-encrypting the data or making a cross-Region call. For more information about multi-Region keys, see Multi-Region keys in KMS in the Key Management Service Developer Guide.
To import your own key material into a KMS key, begin by creating a symmetric
encryption KMS key with no key material. To do this, use the Origin
parameter
of CreateKey
with a value of EXTERNAL
. Next, use GetParametersForImport
operation to get a public key and import token, and use the public key to
encrypt your key material. Then, use ImportKeyMaterial
with your import token
to import the key material. For step-by-step instructions, see Importing Key Material
in the Key Management Service Developer Guide .
This feature supports only symmetric encryption KMS keys, including multi-Region symmetric encryption KMS keys. You cannot import key material into any other type of KMS key.
To create a multi-Region primary key with imported key material, use the
Origin
parameter of CreateKey
with a value of EXTERNAL
and the
MultiRegion
parameter with a value of True
. To create replicas of the
multi-Region primary key, use the ReplicateKey
operation. For instructions,
see Importing key material into multi-Region keys. For more information about multi-Region keys, see Multi-Region keys in KMS
in the Key Management Service Developer Guide.
custom-key-store
Custom key store
A custom key store lets you protect your Amazon Web Services resources using keys in a backing key store that you own and manage. When you request a cryptographic operation with a KMS key in a custom key store, the operation is performed in the backing key store using its cryptographic keys.
KMS supports CloudHSM key stores backed by an CloudHSM cluster and external key stores backed by an external key manager outside of Amazon Web Services. When you create a KMS key in an CloudHSM key store, KMS generates an encryption key in the CloudHSM cluster and associates it with the KMS key. When you create a KMS key in an external key store, you specify an existing encryption key in the external key manager.
Some external key managers provide a simpler method for creating a KMS key in an external key store. For details, see your external key manager documentation.
Before you create a KMS key in a custom key store, the ConnectionState
of the
key store must be CONNECTED
. To connect the custom key store, use the
ConnectCustomKeyStore
operation. To find the ConnectionState
, use the
DescribeCustomKeyStores
operation.
To create a KMS key in a custom key store, use the CustomKeyStoreId
. Use the
default KeySpec
value, SYMMETRIC_DEFAULT
, and the default KeyUsage
value,
ENCRYPT_DECRYPT
to create a symmetric encryption key. No other key type is
supported in a custom key store.
To create a KMS key in an CloudHSM key store,
use the Origin
parameter with a value of AWS_CLOUDHSM
. The CloudHSM cluster
that is associated with the custom key store must have at least two active HSMs
in different Availability Zones in the Amazon Web Services Region.
To create a KMS key in an external key store,
use the Origin
parameter with a value of EXTERNAL_KEY_STORE
and an
XksKeyId
parameter that identifies an existing external key.
Some external key managers provide a simpler method for creating a KMS key in an external key store. For details, see your external key manager documentation.
Cross-account use: No. You cannot use this operation to create a KMS key in a different Amazon Web Services account.
Required permissions:
kms:CreateKey (IAM policy). To use the Tags
parameter,
kms:TagResource
(IAM policy). For examples and information about related permissions, see Allow a user to create KMS
keys
in the Key Management Service Developer Guide.
related-operations
Related operations:
DescribeKey
ListKeys
ScheduleKeyDeletion
Decrypts ciphertext that was encrypted by a KMS key using any of the following operations:
Encrypt
GenerateDataKey
GenerateDataKeyPair
GenerateDataKeyWithoutPlaintext
GenerateDataKeyPairWithoutPlaintext
You can use this operation to decrypt ciphertext that was encrypted under a symmetric encryption KMS key or an asymmetric encryption KMS key.
When the KMS key is asymmetric, you must specify the KMS key and the encryption algorithm that was used to encrypt the ciphertext. For information about asymmetric KMS keys, see Asymmetric KMS keys in the Key Management Service Developer Guide.
The Decrypt
operation also decrypts ciphertext that was encrypted outside of
KMS by the public key in an KMS asymmetric KMS key. However, it cannot decrypt
symmetric ciphertext produced by other libraries, such as the Amazon Web Services Encryption
SDK or
Amazon S3 client-side encryption.
These libraries return a ciphertext format that is incompatible with KMS.
If the ciphertext was encrypted under a symmetric encryption KMS key, the
KeyId
parameter is optional. KMS can get this information from metadata that
it adds to the symmetric ciphertext blob. This feature adds durability to your
implementation by ensuring that authorized users can decrypt ciphertext decades
after it was encrypted, even if they've lost track of the key ID. However,
specifying the KMS key is always recommended as a best practice. When you use
the KeyId
parameter to specify a KMS key, KMS only uses the KMS key you
specify. If the ciphertext was encrypted under a different KMS key, the
Decrypt
operation fails. This practice ensures that you use the KMS key that
you intend.
Whenever possible, use key policies to give users permission to call the
Decrypt
operation on a particular KMS key, instead of using &IAM; policies.
Otherwise, you might create an &IAM; policy that gives the user Decrypt
permission on all KMS keys. This user could decrypt ciphertext that was
encrypted by KMS keys in other accounts if the key policy for the cross-account
KMS key permits it. If you must use an IAM policy for Decrypt
permissions,
limit the user to particular KMS keys or particular trusted accounts. For
details, see Best practices for IAM policies
in the Key Management Service Developer Guide.
Applications in Amazon Web Services Nitro Enclaves can call this operation by using the Amazon Web Services Nitro Enclaves Development Kit. For information about the supporting parameters, see How Amazon Web Services Nitro Enclaves use KMS in the Key Management Service Developer Guide.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. If you use the KeyId
parameter to identify a KMS
key in a different Amazon Web Services account, specify the key ARN or the alias
ARN of the KMS key.
Required permissions: kms:Decrypt (key policy)
related-operations
Related operations:
Encrypt
GenerateDataKey
GenerateDataKeyPair
ReEncrypt
Deletes the specified alias.
Adding, deleting, or updating an alias can allow or deny permission to the KMS key. For details, see ABAC for KMS in the Key Management Service Developer Guide.
Because an alias is not a property of a KMS key, you can delete and change the
aliases of a KMS key without affecting the KMS key. Also, aliases do not appear
in the response from the DescribeKey
operation. To get the aliases of all KMS
keys, use the ListAliases
operation.
Each KMS key can have multiple aliases. To change the alias of a KMS key, use
DeleteAlias
to delete the current alias and CreateAlias
to create a new
alias. To associate an existing alias with a different KMS key, call
UpdateAlias
.
Cross-account use: No. You cannot perform this operation on an alias in a different Amazon Web Services account.
required-permissions
Required permissions
* kms:DeleteAlias on the alias (IAM policy).
* kms:DeleteAlias on the KMS key (key policy).
For details, see Controlling access to aliases in the Key Management Service Developer Guide.
related-operations
Related operations:
CreateAlias
ListAliases
UpdateAlias
Deletes a custom key store.
This operation does not affect any backing elements of the custom key store. It does not delete the CloudHSM cluster that is associated with an CloudHSM key store, or affect any users or keys in the cluster. For an external key store, it does not affect the external key store proxy, external key manager, or any external keys.
This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.
The custom key store that you delete cannot contain any KMS keys.
Before deleting the key store, verify that you will never need to use any of the
KMS keys in the key store for any cryptographic operations.
Then, use ScheduleKeyDeletion
to delete the KMS keys from the key store. After
the required waiting period expires and all KMS keys are deleted from the custom
key store, use DisconnectCustomKeyStore
to disconnect the key store from KMS.
Then, you can delete the custom key store.
For keys in an CloudHSM key store, the ScheduleKeyDeletion
operation makes a
best effort to delete the key material from the associated cluster. However, you
might need to manually delete the orphaned key material
from the cluster and its backups. KMS never creates, manages, or deletes
cryptographic keys in the external key manager associated with an external key
store. You must manage them using your external key manager tools.
Instead of deleting the custom key store, consider using the
DisconnectCustomKeyStore
operation to disconnect the custom key store from its
backing key store. While the key store is disconnected, you cannot create or use
the KMS keys in the key store. But, you do not need to delete KMS keys and you
can reconnect a disconnected custom key store at any time.
If the operation succeeds, it returns a JSON object with no properties.
Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.
Required permissions: kms:DeleteCustomKeyStore (IAM policy)
related-operations
Related operations:
ConnectCustomKeyStore
CreateCustomKeyStore
DescribeCustomKeyStores
DisconnectCustomKeyStore
UpdateCustomKeyStore
Deletes key material that you previously imported.
This operation makes the specified KMS key unusable. For more information about importing key material into KMS, see Importing Key Material in the Key Management Service Developer Guide.
When the specified KMS key is in the PendingDeletion
state, this operation
does not change the KMS key's state. Otherwise, it changes the KMS key's state
to PendingImport
.
After you delete key material, you can use ImportKeyMaterial
to reimport the
same key material into the KMS key.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:DeleteImportedKeyMaterial (key policy)
related-operations
Related operations:
GetParametersForImport
ImportKeyMaterial
Gets information about custom key stores in the account and Region.
This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.
By default, this operation returns information about all custom key stores in
the account and Region. To get only information about a particular custom key
store, use either the CustomKeyStoreName
or CustomKeyStoreId
parameter (but
not both).
To determine whether the custom key store is connected to its CloudHSM cluster
or external key store proxy, use the ConnectionState
element in the response.
If an attempt to connect the custom key store failed, the ConnectionState
value is FAILED
and the ConnectionErrorCode
element in the response
indicates the cause of the failure. For help interpreting the
ConnectionErrorCode
, see CustomKeyStoresListEntry
.
Custom key stores have a DISCONNECTED
connection state if the key store has
never been connected or you used the DisconnectCustomKeyStore
operation to
disconnect it. Otherwise, the connection state is CONNECTED. If your custom key
store connection state is CONNECTED
but you are having trouble using it,
verify that the backing store is active and available. For an CloudHSM key
store, verify that the associated CloudHSM cluster is active and contains the
minimum number of HSMs required for the operation, if any. For an external key
store, verify that the external key store proxy and its associated external key
manager are reachable and enabled.
For help repairing your CloudHSM key store, see the Troubleshooting CloudHSM key stores. For help repairing your external key store, see the Troubleshooting external key stores. Both topics are in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.
Required permissions: kms:DescribeCustomKeyStores (IAM policy)
related-operations
Related operations:
ConnectCustomKeyStore
CreateCustomKeyStore
DeleteCustomKeyStore
DisconnectCustomKeyStore
UpdateCustomKeyStore
Provides detailed information about a KMS key.
You can run DescribeKey
on a customer managed key
or an Amazon Web Services managed key.
This detailed information includes the key ARN, creation date (and deletion
date, if applicable), the key state, and the origin and expiration date (if any)
of the key material. It includes fields, like KeySpec
, that help you
distinguish different types of KMS keys. It also displays the key usage
(encryption, signing, or generating and verifying MACs) and the algorithms that
the KMS key supports.
For multi-Region keys, DescribeKey
displays the primary key and all related replica keys. For KMS keys in CloudHSM key stores, it includes
information about the key store, such as the key store ID and the CloudHSM
cluster ID. For KMS keys in external key stores, it includes the
custom key store ID and the ID of the external key.
DescribeKey
does not return the following information:
Aliases associated with the KMS key. To get this information, use
ListAliases
.Whether automatic key rotation is enabled on the KMS key. To get this information, use
GetKeyRotationStatus
. Also, some key states prevent a KMS key from being automatically rotated. For details, see How Automatic Key Rotation Works in the Key Management Service Developer Guide.Tags on the KMS key. To get this information, use
ListResourceTags
.Key policies and grants on the KMS key. To get this information, use
GetKeyPolicy
andListGrants
.
In general, DescribeKey
is a non-mutating operation. It returns data about KMS
keys, but doesn't change them. However, Amazon Web Services services use
DescribeKey
to create Amazon Web Services managed keys
from a predefined Amazon Web Services alias with no key ID.
Cross-account use: Yes. To perform this operation with a KMS key in a
different Amazon Web Services account, specify the key ARN or alias ARN in the
value of the KeyId
parameter.
Required permissions: kms:DescribeKey (key policy)
related-operations
Related operations:
GetKeyPolicy
GetKeyRotationStatus
ListAliases
ListGrants
ListKeys
ListResourceTags
ListRetirableGrants
Sets the state of a KMS key to disabled.
This change temporarily prevents use of the KMS key for cryptographic operations.
For more information about how key state affects the use of a KMS key, see Key states of KMS keys in the Key Management Service Developer Guide .
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:DisableKey (key policy)
Related operations: EnableKey
Disables automatic rotation of the key material of the specified symmetric encryption KMS key.
Automatic key rotation is supported only on symmetric encryption KMS keys. You cannot enable automatic rotation of asymmetric KMS keys, HMAC KMS keys, KMS keys with imported key material, or KMS keys in a custom key store. To enable or disable automatic rotation of a set of related multi-Region keys, set the property on the primary key.
You can enable (EnableKeyRotation
) and disable automatic rotation of the key
material in customer managed KMS keys.
Key material rotation of Amazon Web Services managed KMS keys
is not configurable. KMS always rotates the key material for every year.
Rotation of Amazon Web Services owned KMS keys
varies.
In May 2022, KMS changed the rotation schedule for Amazon Web Services managed
keys from every three years to every year. For details, see EnableKeyRotation
.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:DisableKeyRotation (key policy)
related-operations
Related operations:
EnableKeyRotation
GetKeyRotationStatus
Disconnects the custom key store from its backing key store.
This operation disconnects an CloudHSM key store from its associated CloudHSM cluster or disconnects an external key store from the external key store proxy that communicates with your external key manager.
This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.
While a custom key store is disconnected, you can manage the custom key store and its KMS keys, but you cannot create or use its KMS keys. You can reconnect the custom key store at any time.
While a custom key store is disconnected, all attempts to create KMS keys in the custom key store or to use existing KMS keys in cryptographic operations will fail. This action can prevent users from storing and accessing sensitive data.
When you disconnect a custom key store, its ConnectionState
changes to
Disconnected
. To find the connection state of a custom key store, use the
DescribeCustomKeyStores
operation. To reconnect a custom key store, use the
ConnectCustomKeyStore
operation.
If the operation succeeds, it returns a JSON object with no properties.
Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.
Required permissions: kms:DisconnectCustomKeyStore (IAM policy)
related-operations
Related operations:
ConnectCustomKeyStore
CreateCustomKeyStore
DeleteCustomKeyStore
DescribeCustomKeyStores
UpdateCustomKeyStore
Sets the key state of a KMS key to enabled.
This allows you to use the KMS key for cryptographic operations.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:EnableKey (key policy)
Related operations: DisableKey
Enables automatic rotation of the key material of the specified symmetric encryption KMS key.
When you enable automatic rotation of acustomer managed KMS key,
KMS rotates the key material of the KMS key one year (approximately 365 days)
from the enable date and every year thereafter. You can monitor rotation of the
key material for your KMS keys in CloudTrail and Amazon CloudWatch. To disable
rotation of the key material in a customer managed KMS key, use the
DisableKeyRotation
operation.
Automatic key rotation is supported only on symmetric encryption KMS keys. You cannot enable automatic rotation of asymmetric KMS keys, HMAC KMS keys, KMS keys with imported key material, or KMS keys in a custom key store. To enable or disable automatic rotation of a set of related multi-Region keys, set the property on the primary key.
You cannot enable or disable automatic rotation Amazon Web Services managed KMS keys. KMS always rotates the key material of Amazon Web Services managed keys every year. Rotation of Amazon Web Services owned KMS keys varies.
In May 2022, KMS changed the rotation schedule for Amazon Web Services managed keys from every three years (approximately 1,095 days) to every year (approximately 365 days).
New Amazon Web Services managed keys are automatically rotated one year after they are created, and approximately every year thereafter.
Existing Amazon Web Services managed keys are automatically rotated one year after their most recent rotation, and every year thereafter.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:EnableKeyRotation (key policy)
related-operations
Related operations:
DisableKeyRotation
GetKeyRotationStatus
Encrypts plaintext of up to 4,096 bytes using a KMS key.
You can use a symmetric or asymmetric KMS key with a KeyUsage
of
ENCRYPT_DECRYPT
.
You can use this operation to encrypt small amounts of arbitrary data, such as a
personal identifier or database password, or other sensitive information. You
don't need to use the Encrypt
operation to encrypt a data key. The
GenerateDataKey
and GenerateDataKeyPair
operations return a plaintext data
key and an encrypted copy of that data key.
If you use a symmetric encryption KMS key, you can use an encryption context to
add additional security to your encryption operation. If you specify an
EncryptionContext
when encrypting data, you must specify the same encryption
context (a case-sensitive exact match) when decrypting the data. Otherwise, the
request to decrypt fails with an InvalidCiphertextException
. For more
information, see Encryption Context
in the Key Management Service Developer Guide.
If you specify an asymmetric KMS key, you must also specify the encryption algorithm. The algorithm must be compatible with the KMS key spec.
When you use an asymmetric KMS key to encrypt or reencrypt data, be sure to record the KMS key and encryption algorithm that you choose. You will be required to provide the same KMS key and encryption algorithm when you decrypt the data. If the KMS key and algorithm do not match the values used to encrypt the data, the decrypt operation fails.
You are not required to supply the key ID and encryption algorithm when you decrypt with symmetric encryption KMS keys because KMS stores this information in the ciphertext blob. KMS cannot store metadata in ciphertext generated with asymmetric keys. The standard format for asymmetric key ciphertext does not include configurable fields.
The maximum size of the data that you can encrypt varies with the type of KMS key and the encryption algorithm that you choose.
Symmetric encryption KMS keys
SYMMETRIC_DEFAULT
: 4096 bytes
RSA_2048
RSAES_OAEP_SHA_1
: 214 bytesRSAES_OAEP_SHA_256
: 190 bytes
RSA_3072
RSAES_OAEP_SHA_1
: 342 bytesRSAES_OAEP_SHA_256
: 318 bytes
RSA_4096
RSAES_OAEP_SHA_1
: 470 bytesRSAES_OAEP_SHA_256
: 446 bytes
SM2PKE
: 1024 bytes (China Regions only)
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a
different Amazon Web Services account, specify the key ARN or alias ARN in the
value of the KeyId
parameter.
Required permissions: kms:Encrypt (key policy)
related-operations
Related operations:
Decrypt
GenerateDataKey
GenerateDataKeyPair
Returns a unique symmetric data key for use outside of KMS.
This operation returns a plaintext copy of the data key and a copy that is encrypted under a symmetric encryption KMS key that you specify. The bytes in the plaintext key are random; they are not related to the caller or the KMS key. You can use the plaintext key to encrypt your data outside of KMS and store the encrypted data key with the encrypted data.
To generate a data key, specify the symmetric encryption KMS key that will be
used to encrypt the data key. You cannot use an asymmetric KMS key to encrypt
data keys. To get the type of your KMS key, use the DescribeKey
operation.
You must also specify the length of the data key. Use either the KeySpec
or
NumberOfBytes
parameters (but not both). For 128-bit and 256-bit data keys,
use the KeySpec
parameter.
To generate a 128-bit SM4 data key (China Regions only), specify a KeySpec
value of AES_128
or a NumberOfBytes
value of 16
. The symmetric encryption
key used in China Regions to encrypt your data key is an SM4 encryption key.
To get only an encrypted copy of the data key, use
GenerateDataKeyWithoutPlaintext
. To generate an asymmetric data key pair, use
the GenerateDataKeyPair
or GenerateDataKeyPairWithoutPlaintext
operation. To
get a cryptographically secure random byte string, use GenerateRandom
.
You can use an optional encryption context to add additional security to the
encryption operation. If you specify an EncryptionContext
, you must specify
the same encryption context (a case-sensitive exact match) when decrypting the
encrypted data key. Otherwise, the request to decrypt fails with an
InvalidCiphertextException
. For more information, see Encryption Context
in the Key Management Service Developer Guide.
Applications in Amazon Web Services Nitro Enclaves can call this operation by using the Amazon Web Services Nitro Enclaves Development Kit. For information about the supporting parameters, see How Amazon Web Services Nitro Enclaves use KMS in the Key Management Service Developer Guide.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
how-to-use-your-data-key
How to use your data key
We recommend that you use the following pattern to encrypt data locally in your application. You can write your own code or use a client-side encryption library, such as the Amazon Web Services Encryption SDK, the Amazon DynamoDB Encryption Client, or Amazon S3 client-side encryption to do these tasks for you.
To encrypt data outside of KMS:
Use the
GenerateDataKey
operation to get a data key.Use the plaintext data key (in the
Plaintext
field of the response) to encrypt your data outside of KMS. Then erase the plaintext data key from memory.Store the encrypted data key (in the
CiphertextBlob
field of the response) with the encrypted data.
To decrypt data outside of KMS:
Use the
Decrypt
operation to decrypt the encrypted data key. The operation returns a plaintext copy of the data key.Use the plaintext data key to decrypt data outside of KMS, then erase the plaintext data key from memory.
Cross-account use: Yes. To perform this operation with a KMS key in a
different Amazon Web Services account, specify the key ARN or alias ARN in the
value of the KeyId
parameter.
Required permissions: kms:GenerateDataKey (key policy)
related-operations
Related operations:
Decrypt
Encrypt
GenerateDataKeyPair
GenerateDataKeyPairWithoutPlaintext
GenerateDataKeyWithoutPlaintext
Returns a unique asymmetric data key pair for use outside of KMS.
This operation returns a plaintext public key, a plaintext private key, and a copy of the private key that is encrypted under the symmetric encryption KMS key you specify. You can use the data key pair to perform asymmetric cryptography and implement digital signatures outside of KMS. The bytes in the keys are random; they not related to the caller or to the KMS key that is used to encrypt the private key.
You can use the public key that GenerateDataKeyPair
returns to encrypt data or
verify a signature outside of KMS. Then, store the encrypted private key with
the data. When you are ready to decrypt data or sign a message, you can use the
Decrypt
operation to decrypt the encrypted private key.
To generate a data key pair, you must specify a symmetric encryption KMS key to
encrypt the private key in a data key pair. You cannot use an asymmetric KMS key
or a KMS key in a custom key store. To get the type and origin of your KMS key,
use the DescribeKey
operation.
Use the KeyPairSpec
parameter to choose an RSA or Elliptic Curve (ECC) data
key pair. In China Regions, you can also choose an SM2 data key pair. KMS
recommends that you use ECC key pairs for signing, and use RSA and SM2 key pairs
for either encryption or signing, but not both. However, KMS cannot enforce any
restrictions on the use of data key pairs outside of KMS.
If you are using the data key pair to encrypt data, or for any operation where
you don't immediately need a private key, consider using the
GenerateDataKeyPairWithoutPlaintext
operation.
GenerateDataKeyPairWithoutPlaintext
returns a plaintext public key and an
encrypted private key, but omits the plaintext private key that you need only to
decrypt ciphertext or sign a message. Later, when you need to decrypt the data
or sign a message, use the Decrypt
operation to decrypt the encrypted private
key in the data key pair.
GenerateDataKeyPair
returns a unique data key pair for each request. The bytes
in the keys are random; they are not related to the caller or the KMS key that
is used to encrypt the private key. The public key is a DER-encoded X.509
SubjectPublicKeyInfo, as specified in RFC 5280. The private key is a DER-encoded
PKCS8 PrivateKeyInfo, as specified in RFC 5958.
You can use an optional encryption context to add additional security to the
encryption operation. If you specify an EncryptionContext
, you must specify
the same encryption context (a case-sensitive exact match) when decrypting the
encrypted data key. Otherwise, the request to decrypt fails with an
InvalidCiphertextException
. For more information, see Encryption Context
in the Key Management Service Developer Guide.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a
different Amazon Web Services account, specify the key ARN or alias ARN in the
value of the KeyId
parameter.
Required permissions: kms:GenerateDataKeyPair (key policy)
related-operations
Related operations:
Decrypt
Encrypt
GenerateDataKey
GenerateDataKeyPairWithoutPlaintext
GenerateDataKeyWithoutPlaintext
generate_data_key_pair_without_plaintext(client, input, options \\ [])
View SourceReturns a unique asymmetric data key pair for use outside of KMS.
This operation returns a plaintext public key and a copy of the private key that
is encrypted under the symmetric encryption KMS key you specify. Unlike
GenerateDataKeyPair
, this operation does not return a plaintext private key.
The bytes in the keys are random; they are not related to the caller or to the
KMS key that is used to encrypt the private key.
You can use the public key that GenerateDataKeyPairWithoutPlaintext
returns to
encrypt data or verify a signature outside of KMS. Then, store the encrypted
private key with the data. When you are ready to decrypt data or sign a message,
you can use the Decrypt
operation to decrypt the encrypted private key.
To generate a data key pair, you must specify a symmetric encryption KMS key to
encrypt the private key in a data key pair. You cannot use an asymmetric KMS key
or a KMS key in a custom key store. To get the type and origin of your KMS key,
use the DescribeKey
operation.
Use the KeyPairSpec
parameter to choose an RSA or Elliptic Curve (ECC) data
key pair. In China Regions, you can also choose an SM2 data key pair. KMS
recommends that you use ECC key pairs for signing, and use RSA and SM2 key pairs
for either encryption or signing, but not both. However, KMS cannot enforce any
restrictions on the use of data key pairs outside of KMS.
GenerateDataKeyPairWithoutPlaintext
returns a unique data key pair for each
request. The bytes in the key are not related to the caller or KMS key that is
used to encrypt the private key. The public key is a DER-encoded X.509
SubjectPublicKeyInfo, as specified in RFC 5280.
You can use an optional encryption context to add additional security to the
encryption operation. If you specify an EncryptionContext
, you must specify
the same encryption context (a case-sensitive exact match) when decrypting the
encrypted data key. Otherwise, the request to decrypt fails with an
InvalidCiphertextException
. For more information, see Encryption Context
in the Key Management Service Developer Guide.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a
different Amazon Web Services account, specify the key ARN or alias ARN in the
value of the KeyId
parameter.
Required permissions: kms:GenerateDataKeyPairWithoutPlaintext (key policy)
related-operations
Related operations:
Decrypt
Encrypt
GenerateDataKey
GenerateDataKeyPair
GenerateDataKeyWithoutPlaintext
Returns a unique symmetric data key for use outside of KMS.
This operation returns a data key that is encrypted under a symmetric encryption KMS key that you specify. The bytes in the key are random; they are not related to the caller or to the KMS key.
GenerateDataKeyWithoutPlaintext
is identical to the GenerateDataKey
operation except that it does not return a plaintext copy of the data key.
This operation is useful for systems that need to encrypt data at some point,
but not immediately. When you need to encrypt the data, you call the Decrypt
operation on the encrypted copy of the key.
It's also useful in distributed systems with different levels of trust. For example, you might store encrypted data in containers. One component of your system creates new containers and stores an encrypted data key with each container. Then, a different component puts the data into the containers. That component first decrypts the data key, uses the plaintext data key to encrypt data, puts the encrypted data into the container, and then destroys the plaintext data key. In this system, the component that creates the containers never sees the plaintext data key.
To request an asymmetric data key pair, use the GenerateDataKeyPair
or
GenerateDataKeyPairWithoutPlaintext
operations.
To generate a data key, you must specify the symmetric encryption KMS key that
is used to encrypt the data key. You cannot use an asymmetric KMS key or a key
in a custom key store to generate a data key. To get the type of your KMS key,
use the DescribeKey
operation.
You must also specify the length of the data key. Use either the KeySpec
or
NumberOfBytes
parameters (but not both). For 128-bit and 256-bit data keys,
use the KeySpec
parameter.
To generate an SM4 data key (China Regions only), specify a KeySpec
value of
AES_128
or NumberOfBytes
value of 128
. The symmetric encryption key used
in China Regions to encrypt your data key is an SM4 encryption key.
If the operation succeeds, you will find the encrypted copy of the data key in
the CiphertextBlob
field.
You can use an optional encryption context to add additional security to the
encryption operation. If you specify an EncryptionContext
, you must specify
the same encryption context (a case-sensitive exact match) when decrypting the
encrypted data key. Otherwise, the request to decrypt fails with an
InvalidCiphertextException
. For more information, see Encryption Context
in the Key Management Service Developer Guide.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a
different Amazon Web Services account, specify the key ARN or alias ARN in the
value of the KeyId
parameter.
Required permissions: kms:GenerateDataKeyWithoutPlaintext (key policy)
related-operations
Related operations:
Decrypt
Encrypt
GenerateDataKey
GenerateDataKeyPair
GenerateDataKeyPairWithoutPlaintext
Generates a hash-based message authentication code (HMAC) for a message using an HMAC KMS key and a MAC algorithm that the key supports.
HMAC KMS keys and the HMAC algorithms that KMS uses conform to industry
standards defined in RFC 2104. You can use value that GenerateMac returns in the VerifyMac
operation to
demonstrate that the original message has not changed. Also, because a secret
key is used to create the hash, you can verify that the party that generated the
hash has the required secret key. You can also use the raw result to implement
HMAC-based algorithms such as key derivation functions. This operation is part
of KMS support for HMAC KMS keys. For details, see HMAC keys in
KMS in the
Key Management Service Developer Guide .
Best practices recommend that you limit the time during which any signing mechanism, including an HMAC, is effective. This deters an attack where the actor uses a signed message to establish validity repeatedly or long after the message is superseded. HMAC tags do not include a timestamp, but you can include a timestamp in the token or message to help you detect when its time to refresh the HMAC.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a
different Amazon Web Services account, specify the key ARN or alias ARN in the
value of the KeyId
parameter.
Required permissions: kms:GenerateMac (key policy)
Related operations: VerifyMac
Returns a random byte string that is cryptographically secure.
You must use the NumberOfBytes
parameter to specify the length of the random
byte string. There is no default value for string length.
By default, the random byte string is generated in KMS. To generate the byte
string in the CloudHSM cluster associated with an CloudHSM key store, use the
CustomKeyStoreId
parameter.
Applications in Amazon Web Services Nitro Enclaves can call this operation by using the Amazon Web Services Nitro Enclaves Development Kit. For information about the supporting parameters, see How Amazon Web Services Nitro Enclaves use KMS in the Key Management Service Developer Guide.
For more information about entropy and random number generation, see Key Management Service Cryptographic Details.
Cross-account use: Not applicable. GenerateRandom
does not use any
account-specific resources, such as KMS keys.
Required permissions: kms:GenerateRandom (IAM policy)
Gets a key policy attached to the specified KMS key.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:GetKeyPolicy (key policy)
Related operations: PutKeyPolicy
Gets a Boolean value that indicates whether automatic rotation of the key material is enabled for the specified KMS key.
When you enable automatic rotation for customer managed KMS keys, KMS rotates the key material of the KMS key one year (approximately 365 days) from the enable date and every year thereafter. You can monitor rotation of the key material for your KMS keys in CloudTrail and Amazon CloudWatch.
Automatic key rotation is supported only on symmetric encryption KMS keys. You cannot enable automatic rotation of asymmetric KMS keys, HMAC KMS keys, KMS keys with imported key material, or KMS keys in a custom key store. To enable or disable automatic rotation of a set of related multi-Region keys, set the property on the primary key..
You can enable (EnableKeyRotation
) and disable automatic rotation
(DisableKeyRotation
) of the key material in customer managed KMS keys. Key
material rotation of Amazon Web Services managed KMS keys
is not configurable. KMS always rotates the key material in Amazon Web Services
managed KMS keys every year. The key rotation status for Amazon Web Services
managed KMS keys is always true
.
In May 2022, KMS changed the rotation schedule for Amazon Web Services managed
keys from every three years to every year. For details, see EnableKeyRotation
.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Disabled: The key rotation status does not change when you disable a KMS key. However, while the KMS key is disabled, KMS does not rotate the key material. When you re-enable the KMS key, rotation resumes. If the key material in the re-enabled KMS key hasn't been rotated in one year, KMS rotates it immediately, and every year thereafter. If it's been less than a year since the key material in the re-enabled KMS key was rotated, the KMS key resumes its prior rotation schedule.
Pending deletion: While a KMS key is pending deletion, its key rotation status is
false
and KMS does not rotate the key material. If you cancel the deletion, the original key rotation status returns totrue
.
Cross-account use: Yes. To perform this operation on a KMS key in a
different Amazon Web Services account, specify the key ARN in the value of the
KeyId
parameter.
Required permissions: kms:GetKeyRotationStatus (key policy)
related-operations
Related operations:
DisableKeyRotation
EnableKeyRotation
Returns the items you need to import key material into a symmetric encryption KMS key.
For more information about importing key material into KMS, see Importing key material in the Key Management Service Developer Guide.
This operation returns a public key and an import token. Use the public key to
encrypt the symmetric key material. Store the import token to send with a
subsequent ImportKeyMaterial
request.
You must specify the key ID of the symmetric encryption KMS key into which you
will import key material. The KMS key Origin
must be EXTERNAL
. You must also
specify the wrapping algorithm and type of wrapping key (public key) that you
will use to encrypt the key material. You cannot perform this operation on an
asymmetric KMS key, an HMAC KMS key, or on any KMS key in a different Amazon Web
Services account.
To import key material, you must use the public key and import token from the
same response. These items are valid for 24 hours. The expiration date and time
appear in the GetParametersForImport
response. You cannot use an expired token
in an ImportKeyMaterial
request. If your key and token expire, send another
GetParametersForImport
request.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:GetParametersForImport (key policy)
related-operations
Related operations:
ImportKeyMaterial
DeleteImportedKeyMaterial
Returns the public key of an asymmetric KMS key.
Unlike the private key of a asymmetric KMS key, which never leaves KMS
unencrypted, callers with kms:GetPublicKey
permission can download the public
key of an asymmetric KMS key. You can share the public key to allow others to
encrypt messages and verify signatures outside of KMS. For information about
asymmetric KMS keys, see Asymmetric KMS keys
in the Key Management Service Developer Guide.
You do not need to download the public key. Instead, you can use the public key
within KMS by calling the Encrypt
, ReEncrypt
, or Verify
operations with
the identifier of an asymmetric KMS key. When you use the public key within KMS,
you benefit from the authentication, authorization, and logging that are part of
every KMS operation. You also reduce of risk of encrypting data that cannot be
decrypted. These features are not effective outside of KMS.
To help you use the public key safely outside of KMS, GetPublicKey
returns
important information about the public key in the response, including:
*
KeySpec: The type of key material in the public key, such as RSA_4096
or
ECC_NIST_P521
.
* KeyUsage: Whether the key is used for encryption or signing.
* EncryptionAlgorithms or SigningAlgorithms: A list of the encryption algorithms or the signing algorithms for the key.
Although KMS cannot enforce these restrictions on external operations, it is crucial that you use this information to prevent the public key from being used improperly. For example, you can prevent a public signing key from being used encrypt data, or prevent a public key from being used with an encryption algorithm that is not supported by KMS. You can also avoid errors, such as using the wrong signing algorithm in a verification operation.
To verify a signature outside of KMS with an SM2 public key (China Regions
only), you must specify the distinguishing ID. By default, KMS uses
1234567812345678
as the distinguishing ID. For more information, see Offline verification with SM2 key
pairs.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a
different Amazon Web Services account, specify the key ARN or alias ARN in the
value of the KeyId
parameter.
Required permissions: kms:GetPublicKey (key policy)
Related operations: CreateKey
Imports key material into an existing symmetric encryption KMS key that was created without key material.
After you successfully import key material into a KMS key, you can reimport the same key material into that KMS key, but you cannot import different key material.
You cannot perform this operation on an asymmetric KMS key, an HMAC KMS key, or on any KMS key in a different Amazon Web Services account. For more information about creating KMS keys with no key material and then importing key material, see Importing Key Material in the Key Management Service Developer Guide.
Before using this operation, call GetParametersForImport
. Its response
includes a public key and an import token. Use the public key to encrypt the key
material. Then, submit the import token from the same GetParametersForImport
response.
When calling this operation, you must specify the following values:
- The key ID or key ARN of a KMS key with no key material. Its
Origin
must beEXTERNAL
.
To create a KMS key with no key material, call CreateKey
and set the value of
its Origin
parameter to EXTERNAL
. To get the Origin
of a KMS key, call
DescribeKey
.)
The encrypted key material. To get the public key to encrypt the key material, call
GetParametersForImport
.The import token that
GetParametersForImport
returned. You must use a public key and token from the sameGetParametersForImport
response.Whether the key material expires (
ExpirationModel
) and, if so, when (ValidTo
). If you set an expiration date, on the specified date, KMS deletes the key material from the KMS key, making the KMS key unusable. To use the KMS key in cryptographic operations again, you must reimport the same key material. The only way to change the expiration model or expiration date is by reimporting the same key material and specifying a new expiration date.
When this operation is successful, the key state of the KMS key changes from
PendingImport
to Enabled
, and you can use the KMS key.
If this operation fails, use the exception to help determine the problem. If the
error is related to the key material, the import token, or wrapping key, use
GetParametersForImport
to get a new public key and import token for the KMS
key and repeat the import procedure. For help, see How To Import Key Material
in the Key Management Service Developer Guide.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:ImportKeyMaterial (key policy)
related-operations
Related operations:
DeleteImportedKeyMaterial
GetParametersForImport
Gets a list of aliases in the caller's Amazon Web Services account and region.
For more information about aliases, see CreateAlias
.
By default, the ListAliases
operation returns all aliases in the account and
region. To get only the aliases associated with a particular KMS key, use the
KeyId
parameter.
The ListAliases
response can include aliases that you created and associated
with your customer managed keys, and aliases that Amazon Web Services created
and associated with Amazon Web Services managed keys in your account. You can
recognize Amazon Web Services aliases because their names have the format
aws/<service-name>
, such as aws/dynamodb
.
The response might also include aliases that have no TargetKeyId
field. These
are predefined aliases that Amazon Web Services has created but has not yet
associated with a KMS key. Aliases that Amazon Web Services creates in your
account, including predefined aliases, do not count against your KMS aliases quota.
Cross-account use: No. ListAliases
does not return aliases in other Amazon
Web Services accounts.
Required permissions: kms:ListAliases (IAM policy)
For details, see Controlling access to aliases in the Key Management Service Developer Guide.
related-operations
Related operations:
CreateAlias
DeleteAlias
UpdateAlias
Gets a list of all grants for the specified KMS key.
You must specify the KMS key in all requests. You can filter the grant list by grant ID or grantee principal.
For detailed information about grants, including grant terminology, see Grants in KMS in the Key Management Service Developer Guide . For examples of working with grants in several programming languages, see Programming grants.
The GranteePrincipal
field in the ListGrants
response usually contains the
user or role designated as the grantee principal in the grant. However, when the
grantee principal in the grant is an Amazon Web Services service, the
GranteePrincipal
field contains the service principal,
which might represent several different grantee principals.
Cross-account use: Yes. To perform this operation on a KMS key in a
different Amazon Web Services account, specify the key ARN in the value of the
KeyId
parameter.
Required permissions: kms:ListGrants (key policy)
related-operations
Related operations:
CreateGrant
ListRetirableGrants
RetireGrant
RevokeGrant
Gets the names of the key policies that are attached to a KMS key.
This operation is designed to get policy names that you can use in a
GetKeyPolicy
operation. However, the only valid policy name is default
.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:ListKeyPolicies (key policy)
related-operations
Related operations:
GetKeyPolicy
PutKeyPolicy
Gets a list of all KMS keys in the caller's Amazon Web Services account and Region.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:ListKeys (IAM policy)
related-operations
Related operations:
CreateKey
DescribeKey
ListAliases
ListResourceTags
Returns all tags on the specified KMS key.
For general information about tags, including the format and syntax, see Tagging Amazon Web Services resources in the Amazon Web Services General Reference. For information about using tags in KMS, see Tagging keys.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:ListResourceTags (key policy)
related-operations
Related operations:
CreateKey
ReplicateKey
TagResource
UntagResource
Returns information about all grants in the Amazon Web Services account and Region that have the specified retiring principal.
You can specify any principal in your Amazon Web Services account. The grants
that are returned include grants for KMS keys in your Amazon Web Services
account and other Amazon Web Services accounts. You might use this operation to
determine which grants you may retire. To retire a grant, use the RetireGrant
operation.
For detailed information about grants, including grant terminology, see Grants in KMS in the Key Management Service Developer Guide . For examples of working with grants in several programming languages, see Programming grants.
Cross-account use: You must specify a principal in your Amazon Web Services
account. However, this operation can return grants in any Amazon Web Services
account. You do not need kms:ListRetirableGrants
permission (or any other
additional permission) in any Amazon Web Services account other than your own.
Required permissions: kms:ListRetirableGrants (IAM policy) in your Amazon Web Services account.
related-operations
Related operations:
CreateGrant
ListGrants
RetireGrant
RevokeGrant
Attaches a key policy to the specified KMS key.
For more information about key policies, see Key Policies in the Key Management Service Developer Guide. For help writing and formatting a JSON policy document, see the IAM JSON Policy Reference in the Identity and Access Management User Guide . For examples of adding a key policy in multiple programming languages, see Setting a key policy in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:PutKeyPolicy (key policy)
Related operations: GetKeyPolicy
Decrypts ciphertext and then reencrypts it entirely within KMS.
You can use this operation to change the KMS key under which data is encrypted, such as when you manually rotate a KMS key or change the KMS key that protects a ciphertext. You can also use it to reencrypt ciphertext under the same KMS key, such as to change the encryption context of a ciphertext.
The ReEncrypt
operation can decrypt ciphertext that was encrypted by using a
KMS key in an KMS operation, such as Encrypt
or GenerateDataKey
. It can also
decrypt ciphertext that was encrypted by using the public key of an asymmetric KMS
key
outside of KMS. However, it cannot decrypt ciphertext produced by other
libraries, such as the Amazon Web Services Encryption SDK or
Amazon S3 client-side encryption.
These libraries return a ciphertext format that is incompatible with KMS.
When you use the ReEncrypt
operation, you need to provide information for the
decrypt operation and the subsequent encrypt operation.
If your ciphertext was encrypted under an asymmetric KMS key, you must use the
SourceKeyId
parameter to identify the KMS key that encrypted the ciphertext. You must also supply the encryption algorithm that was used. This information is required to decrypt the data.If your ciphertext was encrypted under a symmetric encryption KMS key, the
SourceKeyId
parameter is optional. KMS can get this information from metadata that it adds to the symmetric ciphertext blob. This feature adds durability to your implementation by ensuring that authorized users can decrypt ciphertext decades after it was encrypted, even if they've lost track of the key ID. However, specifying the source KMS key is always recommended as a best practice. When you use theSourceKeyId
parameter to specify a KMS key, KMS uses only the KMS key you specify. If the ciphertext was encrypted under a different KMS key, theReEncrypt
operation fails. This practice ensures that you use the KMS key that you intend.To reencrypt the data, you must use the
DestinationKeyId
parameter to specify the KMS key that re-encrypts the data after it is decrypted. If the destination KMS key is an asymmetric KMS key, you must also provide the encryption algorithm. The algorithm that you choose must be compatible with the KMS key.
When you use an asymmetric KMS key to encrypt or reencrypt data, be sure to record the KMS key and encryption algorithm that you choose. You will be required to provide the same KMS key and encryption algorithm when you decrypt the data. If the KMS key and algorithm do not match the values used to encrypt the data, the decrypt operation fails.
You are not required to supply the key ID and encryption algorithm when you decrypt with symmetric encryption KMS keys because KMS stores this information in the ciphertext blob. KMS cannot store metadata in ciphertext generated with asymmetric keys. The standard format for asymmetric key ciphertext does not include configurable fields.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. The source KMS key and destination KMS key can be in different Amazon Web Services accounts. Either or both KMS keys can be in a different account than the caller. To specify a KMS key in a different account, you must use its key ARN or alias ARN.
Required permissions:
* kms:ReEncryptFrom permission on the source KMS key (key policy)
* kms:ReEncryptTo permission on the destination KMS key (key policy)
To permit reencryption from or to a KMS key, include the "kms:ReEncrypt*"
permission in your key policy.
This permission is automatically included in the key policy when you use the
console to create a KMS key. But you must include it manually when you create a
KMS key programmatically or when you use the PutKeyPolicy
operation to set a
key policy.
related-operations
Related operations:
Decrypt
Encrypt
GenerateDataKey
GenerateDataKeyPair
Replicates a multi-Region key into the specified Region.
This operation creates a multi-Region replica key based on a multi-Region
primary key in a different Region of the same Amazon Web Services partition. You
can create multiple replicas of a primary key, but each must be in a different
Region. To create a multi-Region primary key, use the CreateKey
operation.
This operation supports multi-Region keys, an KMS feature that lets you create multiple interoperable KMS keys in different Amazon Web Services Regions. Because these KMS keys have the same key ID, key material, and other metadata, you can use them interchangeably to encrypt data in one Amazon Web Services Region and decrypt it in a different Amazon Web Services Region without re-encrypting the data or making a cross-Region call. For more information about multi-Region keys, see Multi-Region keys in KMS in the Key Management Service Developer Guide.
A replica key is a fully-functional KMS key that can be used independently of its primary and peer replica keys. A primary key and its replica keys share properties that make them interoperable. They have the same key ID and key material. They also have the same key spec, key usage, key material origin, and automatic key rotation status. KMS automatically synchronizes these shared properties among related multi-Region keys. All other properties of a replica key can differ, including its key policy, tags, aliases, and Key states of KMS keys. KMS pricing and quotas for KMS keys apply to each primary key and replica key.
When this operation completes, the new replica key has a transient key state of
Creating
. This key state changes to Enabled
(or PendingImport
) after a few
seconds when the process of creating the new replica key is complete. While the
key state is Creating
, you can manage key, but you cannot yet use it in
cryptographic operations. If you are creating and using the replica key
programmatically, retry on KMSInvalidStateException
or call DescribeKey
to
check its KeyState
value before using it. For details about the Creating
key
state, see Key states of KMS keys in
the Key Management Service Developer Guide.
You cannot create more than one replica of a primary key in any Region. If the
Region already includes a replica of the key you're trying to replicate,
ReplicateKey
returns an AlreadyExistsException
error. If the key state of
the existing replica is PendingDeletion
, you can cancel the scheduled key
deletion (CancelKeyDeletion
) or wait for the key to be deleted. The new
replica key you create will have the same shared properties
as the original replica key.
The CloudTrail log of a ReplicateKey
operation records a ReplicateKey
operation in the primary key's Region and a CreateKey
operation in the replica
key's Region.
If you replicate a multi-Region primary key with imported key material, the replica key is created with no key material. You must import the same key material that you imported into the primary key. For details, see Importing key material into multi-Region keys in the Key Management Service Developer Guide.
To convert a replica key to a primary key, use the UpdatePrimaryRegion
operation.
ReplicateKey
uses different default values for the KeyPolicy
and Tags
parameters than those used in the KMS console. For details, see the parameter
descriptions.
Cross-account use: No. You cannot use this operation to create a replica key in a different Amazon Web Services account.
Required permissions:
kms:ReplicateKey
on the primary key (in the primary key's Region). Include this permission in the primary key's key policy.kms:CreateKey
in an IAM policy in the replica Region.To use the
Tags
parameter,kms:TagResource
in an IAM policy in the replica Region.
related-operations
Related operations
CreateKey
UpdatePrimaryRegion
Deletes a grant.
Typically, you retire a grant when you no longer need its permissions. To
identify the grant to retire, use a grant token,
or both the grant ID and a key identifier (key ID or key ARN) of the KMS key.
The CreateGrant
operation returns both values.
This operation can be called by the retiring principal for a grant, by the
grantee principal if the grant allows the RetireGrant
operation, and by the
Amazon Web Services account in which the grant is created. It can also be called
by principals to whom permission for retiring a grant is delegated. For details,
see Retiring and revoking grants
in the Key Management Service Developer Guide.
For detailed information about grants, including grant terminology, see Grants in KMS in the Key Management Service Developer Guide . For examples of working with grants in several programming languages, see Programming grants.
Cross-account use: Yes. You can retire a grant on a KMS key in a different Amazon Web Services account.
Required permissions::Permission to retire a grant is determined primarily by the grant. For details, see Retiring and revoking grants in the Key Management Service Developer Guide.
related-operations
Related operations:
CreateGrant
ListGrants
ListRetirableGrants
RevokeGrant
Deletes the specified grant.
You revoke a grant to terminate the permissions that the grant allows. For more information, see Retiring and revoking grants in the Key Management Service Developer Guide .
When you create, retire, or revoke a grant, there might be a brief delay, usually less than five minutes, until the grant is available throughout KMS. This state is known as eventual consistency. For details, see Eventual consistency in the Key Management Service Developer Guide .
For detailed information about grants, including grant terminology, see Grants in KMS in the Key Management Service Developer Guide . For examples of working with grants in several programming languages, see Programming grants.
Cross-account use: Yes. To perform this operation on a KMS key in a
different Amazon Web Services account, specify the key ARN in the value of the
KeyId
parameter.
Required permissions: kms:RevokeGrant (key policy).
related-operations
Related operations:
CreateGrant
ListGrants
ListRetirableGrants
RetireGrant
Schedules the deletion of a KMS key.
By default, KMS applies a waiting period of 30 days, but you can specify a
waiting period of 7-30 days. When this operation is successful, the key state of
the KMS key changes to PendingDeletion
and the key can't be used in any
cryptographic operations. It remains in this state for the duration of the
waiting period. Before the waiting period ends, you can use CancelKeyDeletion
to cancel the deletion of the KMS key. After the waiting period ends, KMS
deletes the KMS key, its key material, and all KMS data associated with it,
including all aliases that refer to it.
Deleting a KMS key is a destructive and potentially dangerous operation. When a
KMS key is deleted, all data that was encrypted under the KMS key is
unrecoverable. (The only exception is a multi-Region replica key.) To prevent
the use of a KMS key without deleting it, use DisableKey
.
You can schedule the deletion of a multi-Region primary key and its replica keys
at any time. However, KMS will not delete a multi-Region primary key with
existing replica keys. If you schedule the deletion of a primary key with
replicas, its key state changes to PendingReplicaDeletion
and it cannot be
replicated or used in cryptographic operations. This status can continue
indefinitely. When the last of its replicas keys is deleted (not just
scheduled), the key state of the primary key changes to PendingDeletion
and
its waiting period (PendingWindowInDays
) begins. For details, see Deleting multi-Region
keys
in the Key Management Service Developer Guide.
When KMS deletes a KMS key from an CloudHSM key store, it makes a best effort to delete the associated key material from the associated CloudHSM cluster. However, you might need to manually delete the orphaned key material from the cluster and its backups. Deleting a KMS key from an external key store has no effect on the associated external key. However, for both types of custom key stores, deleting a KMS key is destructive and irreversible. You cannot decrypt ciphertext encrypted under the KMS key by using only its associated external key or CloudHSM key. Also, you cannot recreate a KMS key in an external key store by creating a new KMS key with the same key material.
For more information about scheduling a KMS key for deletion, see Deleting KMS keys in the Key Management Service Developer Guide.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:ScheduleKeyDeletion (key policy)
related-operations
Related operations
CancelKeyDeletion
DisableKey
Creates a digital signature for a message or message digest by using the private key in an asymmetric signing KMS key.
To verify the signature, use the Verify
operation, or use the public key in
the same asymmetric KMS key outside of KMS. For information about asymmetric KMS
keys, see Asymmetric KMS
keys
in the Key Management Service Developer Guide.
Digital signatures are generated and verified by using asymmetric key pair, such as an RSA or ECC pair that is represented by an asymmetric KMS key. The key owner (or an authorized user) uses their private key to sign a message. Anyone with the public key can verify that the message was signed with that particular private key and that the message hasn't changed since it was signed.
To use the Sign
operation, provide the following information:
Use the
KeyId
parameter to identify an asymmetric KMS key with aKeyUsage
value ofSIGN_VERIFY
. To get theKeyUsage
value of a KMS key, use theDescribeKey
operation. The caller must havekms:Sign
permission on the KMS key.Use the
Message
parameter to specify the message or message digest to sign. You can submit messages of up to 4096 bytes. To sign a larger message, generate a hash digest of the message, and then provide the hash digest in theMessage
parameter. To indicate whether the message is a full message or a digest, use theMessageType
parameter.Choose a signing algorithm that is compatible with the KMS key.
When signing a message, be sure to record the KMS key and the signing algorithm. This information is required to verify the signature.
Best practices recommend that you limit the time during which any signature is effective. This deters an attack where the actor uses a signed message to establish validity repeatedly or long after the message is superseded. Signatures do not include a timestamp, but you can include a timestamp in the signed message to help you detect when its time to refresh the signature.
To verify the signature that this operation generates, use the Verify
operation. Or use the GetPublicKey
operation to download the public key and
then use the public key to verify the signature outside of KMS.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a
different Amazon Web Services account, specify the key ARN or alias ARN in the
value of the KeyId
parameter.
Required permissions: kms:Sign (key policy)
Related operations: Verify
Adds or edits tags on a customer managed key.
Tagging or untagging a KMS key can allow or deny permission to the KMS key. For details, see ABAC for KMS in the Key Management Service Developer Guide.
Each tag consists of a tag key and a tag value, both of which are case-sensitive strings. The tag value can be an empty (null) string. To add a tag, specify a new tag key and a tag value. To edit a tag, specify an existing tag key and a new tag value.
You can use this operation to tag a customer managed key,
but you cannot tag an Amazon Web Services managed key,
an Amazon Web Services owned key,
a custom key store,
or an
alias. You can also add tags to a KMS key while creating it (CreateKey
) or
replicating it (ReplicateKey
).
For information about using tags in KMS, see Tagging keys. For general information about tags, including the format and syntax, see Tagging Amazon Web Services resources in the Amazon Web Services General Reference.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:TagResource (key policy)
related-operations
Related operations
CreateKey
ListResourceTags
ReplicateKey
UntagResource
Deletes tags from a customer managed key.
To delete a tag, specify the tag key and the KMS key.
Tagging or untagging a KMS key can allow or deny permission to the KMS key. For details, see ABAC for KMS in the Key Management Service Developer Guide.
When it succeeds, the UntagResource
operation doesn't return any output. Also,
if the specified tag key isn't found on the KMS key, it doesn't throw an
exception or return a response. To confirm that the operation worked, use the
ListResourceTags
operation.
For information about using tags in KMS, see Tagging keys. For general information about tags, including the format and syntax, see Tagging Amazon Web Services resources in the Amazon Web Services General Reference.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:UntagResource (key policy)
related-operations
Related operations
CreateKey
ListResourceTags
ReplicateKey
TagResource
Associates an existing KMS alias with a different KMS key.
Each alias is associated with only one KMS key at a time, although a KMS key can have multiple aliases. The alias and the KMS key must be in the same Amazon Web Services account and Region.
Adding, deleting, or updating an alias can allow or deny permission to the KMS key. For details, see ABAC for KMS in the Key Management Service Developer Guide.
The current and new KMS key must be the same type (both symmetric or both
asymmetric or both HMAC), and they must have the same key usage. This
restriction prevents errors in code that uses aliases. If you must assign an
alias to a different type of KMS key, use DeleteAlias
to delete the old alias
and CreateAlias
to create a new alias.
You cannot use UpdateAlias
to change an alias name. To change an alias name,
use DeleteAlias
to delete the old alias and CreateAlias
to create a new
alias.
Because an alias is not a property of a KMS key, you can create, update, and
delete the aliases of a KMS key without affecting the KMS key. Also, aliases do
not appear in the response from the DescribeKey
operation. To get the aliases
of all KMS keys in the account, use the ListAliases
operation.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
required-permissions
Required permissions
* kms:UpdateAlias on the alias (IAM policy).
* kms:UpdateAlias on the current KMS key (key policy).
* kms:UpdateAlias on the new KMS key (key policy).
For details, see Controlling access to aliases in the Key Management Service Developer Guide.
related-operations
Related operations:
CreateAlias
DeleteAlias
ListAliases
Changes the properties of a custom key store.
You can use this operation to change the properties of an CloudHSM key store or an external key store.
Use the required CustomKeyStoreId
parameter to identify the custom key store.
Use the remaining optional parameters to change its properties. This operation
does not return any property values. To verify the updated property values, use
the DescribeCustomKeyStores
operation.
This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.
When updating the properties of an external key store, verify that the updated settings connect your key store, via the external key store proxy, to the same external key manager as the previous settings, or to a backup or snapshot of the external key manager with the same cryptographic keys. If the updated connection settings fail, you can fix them and retry, although an extended delay might disrupt Amazon Web Services services. However, if KMS permanently loses its access to cryptographic keys, ciphertext encrypted under those keys is unrecoverable.
For external key stores:
Some external key managers provide a simpler method for updating an external key store. For details, see your external key manager documentation.
When updating an external key store in the KMS console, you can upload a
JSON-based proxy configuration file with the desired values. You cannot upload
the proxy configuration file to the UpdateCustomKeyStore
operation. However,
you can use the file to help you determine the correct values for the
UpdateCustomKeyStore
parameters.
For an CloudHSM key store, you can use this operation to change the custom key
store friendly name (NewCustomKeyStoreName
), to tell KMS about a change to the
kmsuser
crypto user password (KeyStorePassword
), or to associate the custom
key store with a different, but related, CloudHSM cluster (CloudHsmClusterId
).
To update any property of an CloudHSM key store, the ConnectionState
of the
CloudHSM key store must be DISCONNECTED
.
For an external key store, you can use this operation to change the custom key
store friendly name (NewCustomKeyStoreName
), or to tell KMS about a change to
the external key store proxy authentication credentials
(XksProxyAuthenticationCredential
), connection method
(XksProxyConnectivity
), external proxy endpoint (XksProxyUriEndpoint
) and
path (XksProxyUriPath
). For external key stores with an XksProxyConnectivity
of VPC_ENDPOINT_SERVICE
, you can also update the Amazon VPC endpoint service
name (XksProxyVpcEndpointServiceName
). To update most properties of an
external key store, the ConnectionState
of the external key store must be
DISCONNECTED
. However, you can update the CustomKeyStoreName
,
XksProxyAuthenticationCredential
, and XksProxyUriPath
of an external key
store when it is in the CONNECTED or DISCONNECTED state.
If your update requires a DISCONNECTED
state, before using
UpdateCustomKeyStore
, use the DisconnectCustomKeyStore
operation to
disconnect the custom key store. After the UpdateCustomKeyStore
operation
completes, use the ConnectCustomKeyStore
to reconnect the custom key store. To
find the ConnectionState
of the custom key store, use the
DescribeCustomKeyStores
operation.
Before updating the custom key store, verify that the new values allow KMS to
connect the custom key store to its backing key store. For example, before you
change the XksProxyUriPath
value, verify that the external key store proxy is
reachable at the new path.
If the operation succeeds, it returns a JSON object with no properties.
Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.
Required permissions: kms:UpdateCustomKeyStore (IAM policy)
related-operations
Related operations:
ConnectCustomKeyStore
CreateCustomKeyStore
DeleteCustomKeyStore
DescribeCustomKeyStores
DisconnectCustomKeyStore
Updates the description of a KMS key.
To see the description of a KMS key, use DescribeKey
.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.
Required permissions: kms:UpdateKeyDescription (key policy)
related-operations
Related operations
CreateKey
DescribeKey
Changes the primary key of a multi-Region key.
This operation changes the replica key in the specified Region to a primary key
and changes the former primary key to a replica key. For example, suppose you
have a primary key in us-east-1
and a replica key in eu-west-2
. If you run
UpdatePrimaryRegion
with a PrimaryRegion
value of eu-west-2
, the primary
key is now the key in eu-west-2
, and the key in us-east-1
becomes a replica
key. For details, see Updating the primary Region
in the Key Management Service Developer Guide.
This operation supports multi-Region keys, an KMS feature that lets you create multiple interoperable KMS keys in different Amazon Web Services Regions. Because these KMS keys have the same key ID, key material, and other metadata, you can use them interchangeably to encrypt data in one Amazon Web Services Region and decrypt it in a different Amazon Web Services Region without re-encrypting the data or making a cross-Region call. For more information about multi-Region keys, see Multi-Region keys in KMS in the Key Management Service Developer Guide.
The primary key of a multi-Region key is the source for properties that are always shared by primary and replica keys, including the key material, key ID, key spec, key usage, key material origin, and automatic key rotation. It's the only key that can be replicated. You cannot delete the primary key until all replica keys are deleted.
The key ID and primary Region that you specify uniquely identify the replica key
that will become the primary key. The primary Region must already have a replica
key. This operation does not create a KMS key in the specified Region. To find
the replica keys, use the DescribeKey
operation on the primary key or any
replica key. To create a replica key, use the ReplicateKey
operation.
You can run this operation while using the affected multi-Region keys in cryptographic operations. This operation should not delay, interrupt, or cause failures in cryptographic operations.
Even after this operation completes, the process of updating the primary Region
might still be in progress for a few more seconds. Operations such as
DescribeKey
might display both the old and new primary keys as replicas. The
old and new primary keys have a transient key state of Updating
. The original
key state is restored when the update is complete. While the key state is
Updating
, you can use the keys in cryptographic operations, but you cannot
replicate the new primary key or perform certain management operations, such as
enabling or disabling these keys. For details about the Updating
key state,
see Key states of KMS keys in
the Key Management Service Developer Guide.
This operation does not return any output. To verify that primary key is
changed, use the DescribeKey
operation.
Cross-account use: No. You cannot use this operation in a different Amazon Web Services account.
Required permissions:
kms:UpdatePrimaryRegion
on the current primary key (in the primary key's Region). Include this permission primary key's key policy.kms:UpdatePrimaryRegion
on the current replica key (in the replica key's Region). Include this permission in the replica key's key policy.
related-operations
Related operations
CreateKey
ReplicateKey
Verifies a digital signature that was generated by the Sign
operation.
Verification confirms that an authorized user signed the message with the
specified KMS key and signing algorithm, and the message hasn't changed since it
was signed. If the signature is verified, the value of the SignatureValid
field in the response is True
. If the signature verification fails, the
Verify
operation fails with an KMSInvalidSignatureException
exception.
A digital signature is generated by using the private key in an asymmetric KMS key. The signature is verified by using the public key in the same asymmetric KMS key. For information about asymmetric KMS keys, see Asymmetric KMS keys in the Key Management Service Developer Guide.
To use the Verify
operation, specify the same asymmetric KMS key, message, and
signing algorithm that were used to produce the signature. The message type does
not need to be the same as the one used for signing, but it must indicate
whether the value of the Message
parameter should be hashed as part of the
verification process.
You can also verify the digital signature by using the public key of the KMS key
outside of KMS. Use the GetPublicKey
operation to download the public key in
the asymmetric KMS key and then use the public key to verify the signature
outside of KMS. The advantage of using the Verify
operation is that it is
performed within KMS. As a result, it's easy to call, the operation is performed
within the FIPS boundary, it is logged in CloudTrail, and you can use key policy
and IAM policy to determine who is authorized to use the KMS key to verify
signatures.
To verify a signature outside of KMS with an SM2 public key (China Regions
only), you must specify the distinguishing ID. By default, KMS uses
1234567812345678
as the distinguishing ID. For more information, see Offline verification with SM2 key
pairs.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a
different Amazon Web Services account, specify the key ARN or alias ARN in the
value of the KeyId
parameter.
Required permissions: kms:Verify (key policy)
Related operations: Sign
Verifies the hash-based message authentication code (HMAC) for a specified message, HMAC KMS key, and MAC algorithm.
To verify the HMAC, VerifyMac
computes an HMAC using the message, HMAC KMS
key, and MAC algorithm that you specify, and compares the computed HMAC to the
HMAC that you specify. If the HMACs are identical, the verification succeeds;
otherwise, it fails. Verification indicates that the message hasn't changed
since the HMAC was calculated, and the specified key was used to generate and
verify the HMAC.
HMAC KMS keys and the HMAC algorithms that KMS uses conform to industry standards defined in RFC 2104. This operation is part of KMS support for HMAC KMS keys. For details, see HMAC keys in KMS in the Key Management Service Developer Guide.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a
different Amazon Web Services account, specify the key ARN or alias ARN in the
value of the KeyId
parameter.
Required permissions: kms:VerifyMac (key policy)
Related operations: GenerateMac