View Source Pdf.Reader.Encryption.StandardHandler (ExPDF v1.0.1)

Parses the PDF /Encrypt dictionary into a %StandardHandler{} struct.

Supports Standard Security Handler revisions R=2 (V=1), R=3 (V=2), R=4 (V=4, Crypt Filters + AES-128), and R=6 (V=5, AES-256, PDF 2.0). Any other /Filter value returns {:error, :encrypted_unsupported_handler}.

This module is a pure data-extraction layer. It does NOT:

Validate /O or /U password hashes.
Derive the file encryption key.
Perform any cryptographic operations.

Those operations are handled by Pdf.Reader.Encryption.V1V2, Pdf.Reader.Encryption.V4, and Pdf.Reader.Encryption.V5.

SecurityHandler struct fields

Field	Source	Default
`:version`	`/V`	`nil`
`:revision`	`/R`	`nil`
`:length`	`/Length`	`nil`
`:o`	`/O` (raw bytes, unwrapped)	`nil`
`:u`	`/U` (raw bytes, unwrapped)	`nil`
`:oe`	`/OE` (V5 only)	`nil`
`:ue`	`/UE` (V5 only)	`nil`
`:perms`	`/Perms` (V5 only, 16 bytes)	`nil`
`:p`	`/P` (32-bit signed integer)	`nil`
`:cf`	`/CF` sub-dict (V4/V5)	`%{}`
`:stm_filter`	`/StmF` name (V4/V5)	`nil`
`:str_filter`	`/StrF` name (V4/V5)	`nil`
`:encrypt_metadata`	`/EncryptMetadata` (V4+)	`true`
`:filter`	`/Filter` name string	`nil`
`:file_key`	populated after authentication	`nil`
`:id`	`/ID[0]` from trailer	`nil`

Spec references

PDF 1.7 (ISO 32000-1) § 7.6.3.1 — Standard Security Handler: https://opensource.adobe.com/dc-acrobat-sdk-docs/standards/pdfstandards/pdf/PDF32000_2008.pdf
PDF 1.7 § 7.6.3.3 — Encryption Key Algorithm (R=2/3/4): https://opensource.adobe.com/dc-acrobat-sdk-docs/standards/pdfstandards/pdf/PDF32000_2008.pdf
PDF 2.0 (ISO 32000-2) § 7.6.4 — Standard Security Handler (R=6, V=5): https://www.pdfa.org/wp-content/uploads/2023/04/ISO_32000_2_2020_PDF_2.0_FDIS.pdf
Mozilla pdf.js src/core/crypto.js (Apache-2.0 reference implementation): https://github.com/mozilla/pdf.js/blob/master/src/core/crypto.js

Summary

Types

t()

Functions

parse(encrypt_dict, doc_id)

Parses an Encrypt dict map (as returned by Pdf.Reader.Parser) into a %StandardHandler{} struct.

Types

t()

@type t() :: %Pdf.Reader.Encryption.StandardHandler{
  cf: %{required(String.t()) => map()},
  encrypt_metadata: boolean(),
  file_key: binary() | nil,
  filter: String.t() | nil,
  id: binary() | nil,
  length: non_neg_integer() | nil,
  o: binary() | nil,
  oe: binary() | nil,
  p: integer() | nil,
  perms: binary() | nil,
  revision: 2 | 3 | 4 | 6 | nil,
  stm_filter: String.t() | nil,
  str_filter: String.t() | nil,
  u: binary() | nil,
  ue: binary() | nil,
  version: 1 | 2 | 4 | 5 | nil
}

Functions

parse(encrypt_dict, doc_id)

@spec parse(map(), binary()) :: {:ok, t()} | {:error, :encrypted_unsupported_handler}

Parses an Encrypt dict map (as returned by Pdf.Reader.Parser) into a %StandardHandler{} struct.

Parameters

encrypt_dict — a plain %{} map where values follow Parser tagging conventions: integers as integers, names as {:name, string}, byte strings as {:string, binary} or {:hex_string, binary}, booleans as booleans, sub-dicts as plain maps.
doc_id — the raw binary of /ID[0] from the document trailer. Stored on the struct as :id for use by key-derivation modules.

Returns

{:ok, %StandardHandler{}} — for /Filter /Standard dicts.
{:error, :encrypted_unsupported_handler} — for any other /Filter value, or when /Filter is absent.

Note: the :file_key field is always nil on return. Authentication and key derivation are handled by V1V2/V4/V5 modules.