Dart

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.

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // 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))

  final key = '394c97881abd989d29c703e48a72b397';
  final tweakKey = 'a7acf51b59649eeea9b33274d8541df4';
  final dataUnit = '4b15c684a152d485fe9937d39b168c29';

  final bd = CkBinData();
  bd.appendEncoded('2f3b9dcfbae729583b1d1ffdd16bb6fe2757329435662a78f0', 'hex');

  final crypt = CkCrypt2();

  crypt.cryptAlgorithm = 'aes';
  crypt.cipherMode = 'xts';
  crypt.keyLength = 128;

  crypt.setEncodedKey(key, 'hex');
  crypt.xtsSetEncodedTweakKey(tweakKey, 'hex');
  crypt.xtsSetEncodedTweakValue(dataUnit, 'hex');

  // In-place encrypt the contents of bd.
  crypt.encryptBd(bd);

  print('CT = ${bd.getEncoded('hexlower')}');

  // Decrypt to revert back to the unencrypted content:
  crypt.decryptBd(bd);

  print('PT = ${bd.getEncoded('hexlower')}');

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