Dart

Example: Hash Text in Chunks

Shows how to generate a final hash, like SHA-256, for a large text by processing it in chunks. Dart

import 'package:chilkat/chilkat.dart';

void main() {
  final crypt = CkCrypt2();
  crypt.hashAlgorithm = 'sha256';
  crypt.charset = 'utf-8';

  final bd = CkBinData();

  final s = 'The quick brown fox jumped over the lazy dog.\r\n';

  // Accumulate the text in a StringBuilder.  We'll demonstrate hashing the text in chunks,
  // and then also hashing the entire text at once to show the results are the same.

  bd.appendString(s, 'utf-8');
  crypt.hashBeginString(s);

  var i = 0;
  while (i < 200) {
    bd.appendString(s, 'utf-8');
    crypt.hashMoreString(s);
    i++;
  }

  // Get the hash in base64 format.
  crypt.encodingMode = 'base64';

  var encodedHash = crypt.hashFinalENC();
  print('Hash computed in chunks: $encodedHash');

  // Let's alternatively compute the hash of the entire amount of data at once,
  // to show the hash computation is the same:
  encodedHash = crypt.hashBdENC(bd);
  print('Hash computed in 1 step: $encodedHash');

  // Output:

  // Hash computed in chunks: unwkVff61k40roRIJizaknreScHaL6frWe37kydXbZQ=
  // Hash computed in 1 step: unwkVff61k40roRIJizaknreScHaL6frWe37kydXbZQ=
}