Dart

Generating Repeatable Random Data for Testing/Debugging

See more PRNG Examples

Demonstrates how to use the Fortuna PRNG to generate random-looking but repeatable non-random data for the purpose of testing and debugging. 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.

  final fortuna = CkPrng();

  // Normally an application would seed the PRNG with entropy from
  // some real random source.  However, sometimes we want the same
  // random sequence of bytes for testing and debugging purposes.
  // This a reason why GetEntropy and AddEntropy are two different methods.
  // An application could omit the call to GetEntropy, and instead pass
  // non-random data to AddEntropy. For example:

  // Seed the PRNG with non-entropy, so we get a repeatable sequence.
  // Note: AddEntropy can be called any number of times.
  fortuna.addEntropy('01020304', 'hex');
  fortuna.addEntropy('hello world', 'ascii');

  // Generate some random data:
  var strRandHex = fortuna.genRandom(16, 'hex');
  var strRandBase64 = fortuna.genRandom(22, 'base64');
  var strRandBase58 = fortuna.genRandom(32, 'base58');

  print('hex random bytes: $strRandHex');
  print('base64 random bytes: $strRandBase64');
  print('base58 random bytes: $strRandBase58');

  // Try it again with a different object to verify that the same results are obtained:
  final fortuna2 = CkPrng();

  fortuna2.addEntropy('01020304', 'hex');
  fortuna2.addEntropy('hello world', 'ascii');

  strRandHex = fortuna2.genRandom(16, 'hex');
  strRandBase64 = fortuna2.genRandom(22, 'base64');
  strRandBase58 = fortuna2.genRandom(32, 'base58');

  print('hex random bytes: $strRandHex');
  print('base64 random bytes: $strRandBase64');
  print('base58 random bytes: $strRandBase58');
}