Visual FoxPro

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.

Visual FoxPro

LOCAL lnSuccess
LOCAL loJpgBytes
LOCAL loCrypt
LOCAL lcIvHex
LOCAL lcKeyHex

lnSuccess = 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.
loJpgBytes = CreateObject('Chilkat.BinData')
lnSuccess = loJpgBytes.LoadFile("qa_data/jpg/starfish.jpg")
IF (lnSuccess <> 1) THEN
    ? "Failed to load JPG file."
    RELEASE loJpgBytes
    CANCEL
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.)
? loJpgBytes.GetEncoded("base64_mime")

* Sample base64_mime JPG data:

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

loCrypt = CreateObject('Chilkat.Crypt2')

* Specify the encryption to be used.
* First we'll do AES-128 CBC
loCrypt.CryptAlgorithm = "aes"
loCrypt.CipherMode = "cbc"
loCrypt.KeyLength = 128

lcIvHex = "000102030405060708090A0B0C0D0E0F"
loCrypt.SetEncodedIV(lcIvHex,"hex")

lcKeyHex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
loCrypt.SetEncodedKey(lcKeyHex,"hex")

* Do the in-place 128-bit AES CBC encryption.
* The contents of jpgBytes are replaced with the encrypted bytes.
lnSuccess = loCrypt.EncryptBd(loJpgBytes)
IF (lnSuccess <> 1) THEN
    ? loCrypt.LastErrorText
    RELEASE loJpgBytes
    RELEASE loCrypt
    CANCEL
ENDIF

* Examine the JPG bytes again.  The bytes should be different because they are encrypted:
? loJpgBytes.GetEncoded("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:
lnSuccess = loCrypt.DecryptBd(loJpgBytes)
IF (lnSuccess <> 1) THEN
    ? loCrypt.LastErrorText
    RELEASE loJpgBytes
    RELEASE loCrypt
    CANCEL
ENDIF

? loJpgBytes.GetEncoded("base64_mime")

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

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

loCrypt.CryptAlgorithm = "chacha20"
loCrypt.KeyLength = 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.
loCrypt.InitialCount = 22

lnSuccess = loCrypt.EncryptBd(loJpgBytes)
* jpgBytes now contains chacha20 encrypted bytes.

lnSuccess = loCrypt.DecryptBd(loJpgBytes)
* jpgBytes is now restored back to the original unencrypted by bytes.

* Save the bytes to a file..
lnSuccess = loJpgBytes.WriteFile("qa_output/starfish.jpg")

? "Success."

RELEASE loJpgBytes
RELEASE loCrypt