Dart

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.

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.

  // Load a small JPG file to be encrypted/decrypted.
  final jpgBytes = CkBinData();
  try {
    jpgBytes.loadFile('qa_data/jpg/starfish.jpg');
  } on ChilkatException {
    print('Failed to load JPG file.');
    return;
  }

  // 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.)
  print(jpgBytes.getEncoded('base64_mime'));

  // Sample base64_mime JPG data:

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

  final crypt = CkCrypt2();

  // Specify the encryption to be used.
  // First we'll do AES-128 CBC
  crypt.cryptAlgorithm = 'aes';
  crypt.cipherMode = 'cbc';
  crypt.keyLength = 128;

  final ivHex = '000102030405060708090A0B0C0D0E0F';
  crypt.setEncodedIV(ivHex, 'hex');

  final keyHex = '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F';
  crypt.setEncodedKey(keyHex, 'hex');

  // Do the in-place 128-bit AES CBC encryption.
  // The contents of jpgBytes are replaced with the encrypted bytes.
  try {
    crypt.encryptBd(jpgBytes);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Examine the JPG bytes again.  The bytes should be different because they are encrypted:
  print(jpgBytes.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:
  try {
    crypt.decryptBd(jpgBytes);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print(jpgBytes.getEncoded('base64_mime'));

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

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

  crypt.cryptAlgorithm = 'chacha20';
  crypt.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.
  crypt.initialCount = 22;

  crypt.encryptBd(jpgBytes);
  // jpgBytes now contains chacha20 encrypted bytes.

  crypt.decryptBd(jpgBytes);
  // jpgBytes is now restored back to the original unencrypted by bytes.

  // Save the bytes to a file..
  jpgBytes.writeFile('qa_output/starfish.jpg');

  print('Success.');
}