EncryptionMethod
in package
PDF encryption algorithms mapped to their encryption dictionary revisions.
RC4-40 uses V1/R2 (40-bit key, PDF 1.1+). RC4-128 uses V2/R3 (128-bit key, PDF 1.4+). AES-128 uses V4/R4 with a crypt filter (PDF 1.6+). AES-256 uses V5/R6 with the extension-level key derivation (PDF 2.0). The PublicKey variants use the same V/R but derive the file encryption key from a PKCS#7 envelope instead of a user/owner password.