(PureBasic) AES OFB Output Feedback Mode Encryption

Demonstrates how to encrypt using AES OFB (Output Feedback) mode.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkCrypt2.pb"

Procedure ChilkatExample()

    ; This example requires the Chilkat API to have been previously unlocked.
    ; See Global Unlock Sample for sample code.

    crypt.i = CkCrypt2::ckCreate()
    If crypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkCrypt2::setCkCryptAlgorithm(crypt, "aes")
    ; Set the cipher mode to Output Feedback
    CkCrypt2::setCkCipherMode(crypt, "ofb")
    CkCrypt2::setCkKeyLength(crypt, 256)

    ; EncodingMode specifies the encoding of the output for
    ; encryption, and the input for decryption.
    ; It may be "hex", "url", "base64", "quoted-printable", or many other choices.
    CkCrypt2::setCkEncodingMode(crypt, "hex")

    ivHex.s = "000102030405060708090A0B0C0D0E0F"
    CkCrypt2::ckSetEncodedIV(crypt,ivHex,"hex")

    ; The secret key must equal the size of the key.  For
    ; 256-bit encryption, the binary secret key is 32 bytes.
    keyHex.s = "603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4"
    CkCrypt2::ckSetEncodedKey(crypt,keyHex,"hex")

    ; Encrypt a string...
    encStr.s = CkCrypt2::ckEncryptStringENC(crypt,"Popular opinions, on subjects not palpable to sense, are often true, but seldom or never the whole truth. -- John Stuart Mill")
    Debug encStr

    decrypt.i = CkCrypt2::ckCreate()
    If decrypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkCrypt2::setCkCryptAlgorithm(decrypt, "aes")
    CkCrypt2::setCkCipherMode(decrypt, "ofb")
    CkCrypt2::setCkKeyLength(decrypt, 256)
    CkCrypt2::setCkEncodingMode(decrypt, "hex")
    CkCrypt2::ckSetEncodedIV(decrypt,ivHex,"hex")
    CkCrypt2::ckSetEncodedKey(decrypt,keyHex,"hex")

    ; Now decrypt:
    decStr.s = CkCrypt2::ckDecryptStringENC(decrypt,encStr)
    Debug decStr


    CkCrypt2::ckDispose(crypt)
    CkCrypt2::ckDispose(decrypt)


    ProcedureReturn
EndProcedure