(Android™) Example for both AES-128 and ChaCha20 to Encrypt Binary Data

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.

Chilkat Android™ Downloads Android™ Java Libraries Android C/C++ Libraries

// 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);

    // 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.
    CkBinData jpgBytes = new CkBinData();
    boolean success = jpgBytes.LoadFile("qa_data/jpg/starfish.jpg");
    if (success != true) {
        Log.i(TAG, "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.)
    Log.i(TAG, jpgBytes.getEncoded("base64_mime"));

    // Sample base64_mime JPG data:

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

    CkCrypt2 crypt = new CkCrypt2();

    // Specify the encryption to be used.
    // First we'll do AES-128 CBC
    crypt.put_CryptAlgorithm("aes");
    crypt.put_CipherMode("cbc");
    crypt.put_KeyLength(128);

    String ivHex = "000102030405060708090A0B0C0D0E0F";
    crypt.SetEncodedIV(ivHex,"hex");

    String 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.
    success = crypt.EncryptBd(jpgBytes);
    if (success != true) {
        Log.i(TAG, crypt.lastErrorText());
        return;
        }

    // Examine the JPG bytes again.  The bytes should be different because they are encrypted:
    Log.i(TAG, 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:
    success = crypt.DecryptBd(jpgBytes);
    if (success != true) {
        Log.i(TAG, crypt.lastErrorText());
        return;
        }

    Log.i(TAG, jpgBytes.getEncoded("base64_mime"));

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

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

    crypt.put_CryptAlgorithm("chacha20");
    crypt.put_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.put_InitialCount(22);

    success = crypt.EncryptBd(jpgBytes);
    // jpgBytes now contains chacha20 encrypted bytes.

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

    // Save the bytes to a file..
    success = jpgBytes.WriteFile("qa_output/starfish.jpg");

    Log.i(TAG, "Success.");

  }

  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."
  }
}