PureBasic

Example for both AES-128 and ChaCha20 to Encrypt Binary Data

See more Encryption Examples

Demonstrates the use of the new EncryptBd and DecryptBd methods introduced in Chilkat v9.5.0.67 to encrypt/decrypt binary bytes.

Note: This example requires Chilkat v9.5.0.67 or greater.

PureBasic

IncludeFile "CkBinData.pb"
IncludeFile "CkCrypt2.pb"

Procedure ChilkatExample()

    success.i = 0

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

    ; Load a small JPG file to be encrypted/decrypted.
    jpgBytes.i = CkBinData::ckCreate()
    If jpgBytes.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkBinData::ckLoadFile(jpgBytes,"qa_data/jpg/starfish.jpg")
    If success <> 1
        Debug "Failed to load JPG file."
        CkBinData::ckDispose(jpgBytes)
        ProcedureReturn
    EndIf

    ; Show the unencrypted JPG bytes in Base64 format.
    ; (The "base64_mime" encoding was added in Chilkat v9.5.0.67.
    ; The "base64" encoding emits a single line of base64, whereas
    ; "base64_mime" will emit multi-line base64 as it would appear
    ; in MIME.)
    Debug CkBinData::ckGetEncoded(jpgBytes,"base64_mime")

    ; Sample base64_mime JPG data:

    ; 	/9j/4AAQSkZJRgABAgEASABIAAD/7Q18UGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABAASAAAAAEA
    ; 	AQBIAAAAAQABOEJJTQPzAAAAAAAIAAAAAAAAAAE4QklNBAoAAAAAAAEAADhCSU0nEAAAAAAACgAB
    ; 	AAAAAAAAAAI4QklNA/UAAAAAAEgAL2ZmAAEAbGZmAAYAAAAAAAEAL2ZmAAEAoZmaAAYAAAAAAAEA
    ; 	MgAAAAEAWgAAAAYAAAAAAAEANQAAAAEALQAAAAYAAAAAAAE4QklNBBQAAAAAAAQAAAABOEJJTQQM
    ; 	...

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

    ; Specify the encryption to be used.
    ; First we'll do AES-128 CBC
    CkCrypt2::setCkCryptAlgorithm(crypt, "aes")
    CkCrypt2::setCkCipherMode(crypt, "cbc")
    CkCrypt2::setCkKeyLength(crypt, 128)

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

    keyHex.s = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
    CkCrypt2::ckSetEncodedKey(crypt,keyHex,"hex")

    ; Do the in-place 128-bit AES CBC encryption.
    ; The contents of jpgBytes are replaced with the encrypted bytes.
    success = CkCrypt2::ckEncryptBd(crypt,jpgBytes)
    If success <> 1
        Debug CkCrypt2::ckLastErrorText(crypt)
        CkBinData::ckDispose(jpgBytes)
        CkCrypt2::ckDispose(crypt)
        ProcedureReturn
    EndIf

    ; Examine the JPG bytes again.  The bytes should be different because they are encrypted:
    Debug CkBinData::ckGetEncoded(jpgBytes,"base64_mime")

    ; Sample base64_mime encrypted JPG data:

    ; 	sbz0babt1WCkQf5xKMdg/baZAcUBO5GVUUDF2BjVqmd+HrqKN+t6hAcqakL/bdo0q9hYmow0Tp1e
    ; 	AQ9V9DOiifQUZqWVkR+kL/c45bq8JGFDvgNl0djPt+yYhV789IB/fPH0upx+/ad++WNOlv1IxGMr
    ; 	Y1x1oERU/IsiEzafUJdI4kZ6FQo2IPGMF/Rm1h79I7hP1yYUFxvJyz+PzaySAUH1nLsNHyDVY5VY
    ; 	O90aH3steRSYbz8C8UF9wQ3qqEIXQNnnixvoNDnmHyY39VoVBI5F6rnPwYDfAk2t8tmuryFqvwAu
    ; 	...

    ; Decrypt to restore back to the original:
    success = CkCrypt2::ckDecryptBd(crypt,jpgBytes)
    If success <> 1
        Debug CkCrypt2::ckLastErrorText(crypt)
        CkBinData::ckDispose(jpgBytes)
        CkCrypt2::ckDispose(crypt)
        ProcedureReturn
    EndIf

    Debug CkBinData::ckGetEncoded(jpgBytes,"base64_mime")

    ; 	/9j/4AAQSkZJRgABAgEASABIAAD/7Q18UGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABAASAAAAAEA
    ; 	AQBIAAAAAQABOEJJTQPzAAAAAAAIAAAAAAAAAAE4QklNBAoAAAAAAAEAADhCSU0nEAAAAAAACgAB
    ; 	AAAAAAAAAAI4QklNA/UAAAAAAEgAL2ZmAAEAbGZmAAYAAAAAAAEAL2ZmAAEAoZmaAAYAAAAAAAEA
    ; 	MgAAAAEAWgAAAAYAAAAAAAEANQAAAAEALQAAAAYAAAAAAAE4QklNBBQAAAAAAAQAAAABOEJJTQQM
    ; 	...

    ; ----------------------------------------------------------------------------------
    ; To do chacha20 encryption, just change the settings:

    CkCrypt2::setCkCryptAlgorithm(crypt, "chacha20")
    CkCrypt2::setCkKeyLength(crypt, 256)
    ; The initial count is the initial block counter for the chacha20 algorithm.
    ; It can be any integer, but must be set to the same when decrypting.
    CkCrypt2::setCkInitialCount(crypt, 22)

    success = CkCrypt2::ckEncryptBd(crypt,jpgBytes)
    ; jpgBytes now contains chacha20 encrypted bytes.

    success = CkCrypt2::ckDecryptBd(crypt,jpgBytes)
    ; jpgBytes is now restored back to the original unencrypted by bytes.

    ; Save the bytes to a file..
    success = CkBinData::ckWriteFile(jpgBytes,"qa_output/starfish.jpg")

    Debug "Success."


    CkBinData::ckDispose(jpgBytes)
    CkCrypt2::ckDispose(crypt)


    ProcedureReturn
EndProcedure