View Source CloudfrontSigner.Policy (cloudfront_signer v1.0.0)

Defines a cloudfront signature policy, and a string coercion method for it

Summary

Types

rsa_private_key()

Type definition for an RSA private key in ASN.1 format. The tuple elements represent

t()

Functions

generate_signature_and_policy(policy, private_key)

Generates a CloudFront URL signature and policy for a given resource.

Types

rsa_private_key()

@type rsa_private_key() ::
  {:RSAPrivateKey, :"two-prime", non_neg_integer(), non_neg_integer(),
   non_neg_integer(), non_neg_integer(), non_neg_integer(), non_neg_integer(),
   non_neg_integer(), non_neg_integer(), :asn1_NOVALUE | [non_neg_integer()]}

Type definition for an RSA private key in ASN.1 format. The tuple elements represent:

  • :RSAPrivateKey - The key type identifier
  • :"two-prime" - The RSA version identifier
  • modulus - The RSA modulus n
  • publicExponent - The public exponent e
  • privateExponent - The private exponent d
  • prime1 - The first prime factor p of n
  • prime2 - The second prime factor q of n
  • exponent1 - d mod (p-1)
  • exponent2 - d mod (q-1)
  • coefficient - The CRT coefficient q^(-1) mod p
  • otherPrimeInfos - Optional additional prime info (usually :asn1_NOVALUE)

t()

@type t() :: %CloudfrontSigner.Policy{expiry: integer(), resource: String.t()}

Functions

generate_signature_and_policy(policy, private_key)

@spec generate_signature_and_policy(t(), rsa_private_key()) ::
  {String.t(), String.t()}

Generates a CloudFront URL signature and policy for a given resource.

Takes a policy struct containing the resource URL and expiry time, along with an RSA private key, and returns a tuple containing the URL-safe base64 encoded signature and the base64 encoded policy.

The signature is generated using SHA-1 with RSA encryption (SHA1withRSA) and is URL-safe encoded. The policy is a JSON document that specifies what resource is being accessed and when the signature expires.

Parameters

  • policy - A Policy struct containing:
    • resource - The URL of the CloudFront resource to be accessed
    • expiry - Unix timestamp when the signature should expire
  • private_key - An RSA private key in ASN.1 format (decoded from PEM)

Returns

  • {signature, encoded_policy} where:
    • signature - URL-safe base64 encoded signature
    • encoded_policy - Base64 encoded JSON policy document