(PureBasic) PBES2 Password-Based Encryption (PBE)

Demonstrates how to implement password-based encryption according to the PKCS #5 v2.0: Password-Based Cryptography Standard (published by RSA Laboratories). This example uses PBES2, which ise based on the PBKDF2 function and an underlying block cipher such as RC2, DES, etc.

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IncludeFile "CkCrypt2.pb"

Procedure ChilkatExample()

    ; This example assumes 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

    ; Set properties for PBES2 encryption:

    CkCrypt2::setCkCryptAlgorithm(crypt, "pbes2")
    CkCrypt2::setCkPbesPassword(crypt, "mySecretPassword")

    ; Set the underlying PBE algorithm (and key length):
    CkCrypt2::setCkPbesAlgorithm(crypt, "rc2")
    CkCrypt2::setCkKeyLength(crypt, 128)
    ; Only required for the RC2 algorithm:
    CkCrypt2::setCkRc2EffectiveKeyLength(crypt, 128)

    ; By definition, the block encryption algorithm (RC2 or whichever
    ; was selected) will run in CBC mode.  Therefore, we need
    ; an IV.  The IV is equal in length to the block size of the
    ; algorithm.  RC2 has a block size of 8 bytes (regardless of
    ; key length), so set the IV to some value that is 8 bytes 
    ; in length:
    CkCrypt2::ckSetEncodedIV(crypt,"0000000000000000","hex")

    ; Give it some salt:
    CkCrypt2::ckSetEncodedSalt(crypt,"0102030405060708","hex")

    ; A higher iteration count makes the algorithm more
    ; computationally expensive and therefore exhaustive
    ; searches (for breaking the encryption) is more difficult:
    CkCrypt2::setCkIterationCount(crypt, 1024)

    ; A hash algorithm needs to be set for PBES2:
    CkCrypt2::setCkHashAlgorithm(crypt, "sha1")

    ; Indicate that the encrypted bytes should be returned
    ; as a hex string:
    CkCrypt2::setCkEncodingMode(crypt, "hex")

    plainText.s = "To be encrypted."

    encryptedText.s = CkCrypt2::ckEncryptStringENC(crypt,plainText)

    Debug encryptedText

    ; Now decrypt:
    decryptedText.s = CkCrypt2::ckDecryptStringENC(crypt,encryptedText)

    Debug decryptedText


    CkCrypt2::ckDispose(crypt)


    ProcedureReturn
EndProcedure