Visual FoxPro

AES XTS Mode

See more Encryption Examples

Demonstrates the AES-XTS mode of operation.

Note: This example requires Chilkat v9.5.0.91 or greater.

Visual FoxPro

LOCAL lnSuccess
LOCAL lcKey
LOCAL lcTweakKey
LOCAL lcDataUnit
LOCAL loBd
LOCAL loCrypt

lnSuccess = 0

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

*  Here we have a sample from CAVS validatition data:

*  COUNT = 301
*  DataUnitLen = 200
*  Key = 
*  394c97881abd989d29c703e48a72b397
*  a7acf51b59649eeea9b33274d8541df4
*  i = 4b15c684a152d485fe9937d39b168c29
*  PT = 2f3b9dcfbae729583b1d1ffdd16bb6fe2757329435662a78f0
*  CT = f3473802e38a3ffef4d4fb8e6aa266ebde553a64528a06463e

*  Note: The above sample requires an AES-XTS implementation that fully supports ciphertext-stealing
*  because the data to be encrypted is not an even multiple of the AES block size (i.e. not a multiple of 16 bytes).
*  Chilkat fully supports AES-XTS with ciphertext stealing.
*  (i.e. Chilkat implements XEX-based tweaked-codebook mode with ciphertext stealing (XTS))

lcKey = "394c97881abd989d29c703e48a72b397"
lcTweakKey = "a7acf51b59649eeea9b33274d8541df4"
lcDataUnit = "4b15c684a152d485fe9937d39b168c29"

loBd = CreateObject('Chilkat.BinData')
loBd.AppendEncoded("2f3b9dcfbae729583b1d1ffdd16bb6fe2757329435662a78f0","hex")

loCrypt = CreateObject('Chilkat.Crypt2')

loCrypt.CryptAlgorithm = "aes"
loCrypt.CipherMode = "xts"
loCrypt.KeyLength = 128

loCrypt.SetEncodedKey(lcKey,"hex")
loCrypt.XtsSetEncodedTweakKey(lcTweakKey,"hex")
loCrypt.XtsSetEncodedTweakValue(lcDataUnit,"hex")

*  In-place encrypt the contents of bd.
lnSuccess = loCrypt.EncryptBd(loBd)

? "CT = " + loBd.GetEncoded("hexlower")

*  Decrypt to revert back to the unencrypted content:
lnSuccess = loCrypt.DecryptBd(loBd)

? "PT = " + loBd.GetEncoded("hexlower")

*  Output:
*  CT = f3473802e38a3ffef4d4fb8e6aa266ebde553a64528a06463e
*  PT = 2f3b9dcfbae729583b1d1ffdd16bb6fe2757329435662a78f0

RELEASE loBd
RELEASE loCrypt