Android™

Fortuna PRNG Generate Random Encoded

See more PRNG Examples

Demonstrates how to generate random bytes using the Fortuna PRNG. The random bytes are returned in an encoded string (using an encoding such as hex, base64, base58, etc.) Android™

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    success = false;

    CkPrng fortuna = new CkPrng();

    // Before beginning to generate random data, 
    // the PRNG (Pseudo Random Number Generator) should
    // be seeded with real random data (also known as "entropy").

    // Note: Accumulating real random data can be difficult
    // and time-consuming to collect.  It is for this reason
    // that pseudorandom data (i.e. a PRNG) is used.  The pseudorandom data generator
    // is seeded with entropy.  In addition, new entropy can (and should)
    // be periodically added as more pseudorandom data is generated.

    // Get 32 bytes of system entropy.  On Linux/Unix systems, this reads
    // from /dev/random.  On MS Windows systems, it uses the Crypto API's 
    // CryptGenRandom function.
    String strEntropy = fortuna.getEntropy(32,"hex");
    if (fortuna.get_LastMethodSuccess() != true) {
        Log.i(TAG, fortuna.lastErrorText());
        return;
        }

    // Seed the PRNG with this entropy:
    success = fortuna.AddEntropy(strEntropy,"hex");
    if (success != true) {
        Log.i(TAG, fortuna.lastErrorText());
        return;
        }

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

    Log.i(TAG, "hex random bytes: " + strRandHex);
    Log.i(TAG, "base64 random bytes: " + strRandBase64);
    Log.i(TAG, "base58 random bytes: " + strRandBase58);

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}