DataFlex

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.

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    String sKey
    String sTweakKey
    String sDataUnit
    Variant vBd
    Handle hoBd
    Handle hoCrypt
    String sTemp1

    Move False To iSuccess

    // 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))

    Move "394c97881abd989d29c703e48a72b397" To sKey
    Move "a7acf51b59649eeea9b33274d8541df4" To sTweakKey
    Move "4b15c684a152d485fe9937d39b168c29" To sDataUnit

    Get Create (RefClass(cComChilkatBinData)) To hoBd
    If (Not(IsComObjectCreated(hoBd))) Begin
        Send CreateComObject of hoBd
    End
    Get ComAppendEncoded Of hoBd "2f3b9dcfbae729583b1d1ffdd16bb6fe2757329435662a78f0" "hex" To iSuccess

    Get Create (RefClass(cComChilkatCrypt2)) To hoCrypt
    If (Not(IsComObjectCreated(hoCrypt))) Begin
        Send CreateComObject of hoCrypt
    End

    Set ComCryptAlgorithm Of hoCrypt To "aes"
    Set ComCipherMode Of hoCrypt To "xts"
    Set ComKeyLength Of hoCrypt To 128

    Send ComSetEncodedKey To hoCrypt sKey "hex"
    Send ComXtsSetEncodedTweakKey To hoCrypt sTweakKey "hex"
    Send ComXtsSetEncodedTweakValue To hoCrypt sDataUnit "hex"

    // In-place encrypt the contents of bd.
    Get pvComObject of hoBd to vBd
    Get ComEncryptBd Of hoCrypt vBd To iSuccess

    Get ComGetEncoded Of hoBd "hexlower" To sTemp1
    Showln "CT = " sTemp1

    // Decrypt to revert back to the unencrypted content:
    Get pvComObject of hoBd to vBd
    Get ComDecryptBd Of hoCrypt vBd To iSuccess

    Get ComGetEncoded Of hoBd "hexlower" To sTemp1
    Showln "PT = " sTemp1

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


End_Procedure