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    #@bobzhang/mbtpdf/core/pdfcryptprimitives

    Cryptographic primitives for PDF encryption and decryption.

    #Overview

    This package provides cryptographic algorithms required for PDF document encryption and decryption, including symmetric ciphers (ARC4, AES), hash functions (MD5, SHA-2 family), and key derivation routines used by the PDF security handler.

    #Types

    #Encryption

    Represents the encryption algorithm types supported by PDF:

    ///|
    pub(all) enum Encryption {
      ARC4(Int, Int) // (bits, /R revision)
      AESV2 // AES-128 CBC (PDF 1.5+)
      AESV3(Bool) // AES-256, Bool indicates ISO mode (revision 6) vs revision 5
    }

    Convenience helper:

    ///|
    pub fn Encryption::r_and_keylength(self : Encryption) -> (Int, Int)

    This returns the PDF security handler revision (/R) and the key length in bits implied by the variant, so callers don't have to repeat the same match.

    #PdfCryptPrimitives

    Cryptography helper context.

    pub struct PdfCryptPrimitives { ... }
    pub fn PdfCryptPrimitives::new() -> PdfCryptPrimitives

    #Methods

    #PdfCryptPrimitives::crypt

    ARC4 stream cipher encryption/decryption. The same function performs both operations since ARC4 is symmetric.

    pub fn PdfCryptPrimitives::crypt(
      self : PdfCryptPrimitives,
      key : Array[Int],
      data : Array[Byte]
    ) -> Array[Byte]

    #PdfCryptPrimitives::md5

    MD5 message digest, returning 16 raw bytes.

    pub fn PdfCryptPrimitives::md5(
      self : PdfCryptPrimitives,
      data : Array[Byte]
    ) -> Array[Byte]

    #PdfCryptPrimitives::sha256

    SHA-256 digest of input data.

    pub fn PdfCryptPrimitives::sha256(
      self : PdfCryptPrimitives,
      input : @pdfio.Input
    ) -> String raise

    #PdfCryptPrimitives::sha384

    SHA-384 digest of input data.

    pub fn PdfCryptPrimitives::sha384(
      self : PdfCryptPrimitives,
      input : @pdfio.Input
    ) -> String raise

    #PdfCryptPrimitives::sha512

    SHA-512 digest of input data.

    pub fn PdfCryptPrimitives::sha512(
      self : PdfCryptPrimitives,
      input : @pdfio.Input
    ) -> String raise

    #PdfCryptPrimitives::aes_encrypt_data

    AES encryption in CBC mode. Returns IV concatenated with ciphertext.

    pub fn PdfCryptPrimitives::aes_encrypt_data(
      self : PdfCryptPrimitives,
      nk : Int,
      key : Array[Int],
      data : Array[Byte],
      firstblock? : Array[Int]
    ) -> Array[Byte]

    • nk: Key length (4 for AES-128, 8 for AES-256)
    • firstblock: Optional IV (random if not provided)

    #PdfCryptPrimitives::aes_decrypt_data

    AES decryption in CBC mode. Expects IV as first 16 bytes of input.

    pub fn PdfCryptPrimitives::aes_decrypt_data(
      self : PdfCryptPrimitives,
      nk : Int,
      key : Array[Int],
      data : Array[Byte],
      remove_padding? : Bool
    ) -> Array[Byte]

    • nk: Key length (4 for AES-128, 8 for AES-256)
    • data: IV + ciphertext
    • remove_padding: Remove PKCS7 padding (default: true)

    #PdfCryptPrimitives::aes_encrypt_data_ecb / PdfCryptPrimitives::aes_decrypt_data_ecb

    AES encryption/decryption in ECB mode (used for specific PDF operations).

    #PdfCryptPrimitives::find_hash

    Apply PDF Algorithm 3.1 to derive the per-object encryption key.

    pub fn PdfCryptPrimitives::find_hash(
      self : PdfCryptPrimitives,
      crypt_type : Encryption,
      obj : Int,
      gen : Int,
      key : Array[Int],
      keylength : Int
    ) -> Array[Int]

    #PdfCryptPrimitives::decrypt_stream_data

    Decrypt or encrypt stream data using the appropriate algorithm based on encryption settings.

    pub fn PdfCryptPrimitives::decrypt_stream_data(
      self : PdfCryptPrimitives,
      crypt_type : Encryption,
      encrypt : Bool,
      file_encryption_key : String?,
      obj : Int,
      gen : Int,
      key : Array[Int],
      keylength : Int,
      r : Int,
      data : Array[Byte]
    ) -> Array[Byte] raise

    • encrypt: true for encryption, false for decryption
    • r: Security handler revision

    #PDF Encryption Support

    This package supports PDF encryption standards:
    • 40-bit RC4 (PDF 1.1): ARC4(40, ...)
    • 128-bit RC4 (PDF 1.4): ARC4(128, ...)
    • 128-bit AES (PDF 1.5): AESV2
    • 256-bit AES (PDF 1.7 Extension 3 / PDF 2.0): AESV3

    Encryption

    source
    pub(all) enum Encryption {
      ARC4(Int, Int)
      AESV2
      AESV3(Bool)
    } derive(
    Debug    )

    Types of encryption.

    Encryption::r_and_keylength

    source
    fn Encryption::r_and_keylength(self : Encryption) -> (Int, Int)

    Return the PDF "revision" (/R) and key length (in bits) implied by the encryption variant.

    • ARC4(bits, r) uses the explicit values from the parsed encryption dict.
    • AESV2 is always revision 4 with a 128-bit key.
    • AESV3(is_iso) is revision 5 (or 6 in ISO mode) with a 256-bit key.

    This is a small convenience API to avoid scattering the same match in multiple packages.

    Encryption::to_repr

    source

    PdfCryptPrimitives

    source
    pub struct PdfCryptPrimitives {
      unit : Unit
    }

    PdfCryptPrimitives::aes_decrypt_data

    source
    fn PdfCryptPrimitives::aes_decrypt_data(_self : PdfCryptPrimitives, nk : Int, key : Array[Int], data : Array[Byte], remove_padding? : Bool) -> Array[Byte]

    [aes_decrypt_data nk key data] decrypts AES data for the given key length, key, and data. If [remove_padding] is true, padding is removed.

    PdfCryptPrimitives::aes_decrypt_data_ecb

    source
    fn PdfCryptPrimitives::aes_decrypt_data_ecb(_self : PdfCryptPrimitives, nk : Int, key : Array[Int], data : Array[Byte], remove_padding? : Bool) -> Array[Byte]

    As [aes_decrypt_data] but in ECB mode.

    PdfCryptPrimitives::aes_encrypt_data

    source
    fn PdfCryptPrimitives::aes_encrypt_data(_self : PdfCryptPrimitives, nk : Int, key : Array[Int], data : Array[Byte], firstblock? : Array[Int]) -> Array[Byte]

    [aes_encrypt_data nk key data] encrypts with AES (CBC), returning IV+data.

    PdfCryptPrimitives::aes_encrypt_data_ecb

    source
    fn PdfCryptPrimitives::aes_encrypt_data_ecb(_self : PdfCryptPrimitives, nk : Int, key : Array[Int], data : Array[Byte]) -> Array[Byte]

    [aes_encrypt_data_ecb nk key data] encrypts data in ECB mode.

    PdfCryptPrimitives::crypt

    source
    fn PdfCryptPrimitives::crypt(_self : PdfCryptPrimitives, key : Array[Int], data : Array[Byte]) -> Array[Byte]

    ARC4 encryption/decryption given a key and some data. The same function performs encryption and decryption.

    PdfCryptPrimitives::decrypt_stream_data

    source
    fn PdfCryptPrimitives::decrypt_stream_data(self : PdfCryptPrimitives, crypt_type : Encryption, encrypt : Bool, file_encryption_key : String?, obj : Int, gen : Int, key : Array[Int], keylength : Int, r : Int, data : Array[Byte]) -> Array[Byte] raise

    Decrypt or encrypt stream data using the active crypt settings.

    PdfCryptPrimitives::find_hash

    source
    fn PdfCryptPrimitives::find_hash(self : PdfCryptPrimitives, crypt_type : Encryption, obj : Int, gen : Int, key : Array[Int], keylength : Int) -> Array[Int]

    Given an object number, generation number, input key and key length in bits, apply Algorithm 3.1 to obtain the hash to be used by the encryption function.

    PdfCryptPrimitives::md5

    source
    fn PdfCryptPrimitives::md5(_self : PdfCryptPrimitives, data : Array[Byte]) -> Array[Byte]

    MD5 digest of bytes, returning 16 raw bytes.

    PdfCryptPrimitives::new

    source

    PdfCryptPrimitives::sha256

    source

    SHA-256 digest of the input stream.

    PdfCryptPrimitives::sha384

    source

    SHA-384 digest of the input stream.

    PdfCryptPrimitives::sha512

    source

    SHA-512 digest of the input stream.

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