(Android™) Encrypt File using X.509 Certificate using AES in CBC Mode

Demonstrates how to encrypt a file using an X.509 Certificate's public key, where the underlying bulk encryption algorithm is 128-bit AES in CBC mode. (The underlying bulk encryption algorithm can be specified to be other algorithms/strengths.)

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 requires the Chilkat Crypt API to have been previously unlocked.
    //  See Unlock Chilkat Crypt for sample code.

    CkCrypt2 crypt = new CkCrypt2();

    //  Use public-key cryptography for encryption.
    crypt.put_CryptAlgorithm("pki");

    //  Get an X.509 certificate to use for encrypting.
    //  Note: Chilkat provides many different ways of loading a certificate, from many different formats,
    //  or if on Windows, from the installed certificates on the system.
    //  This example simply loads a certificate from a file.
    //  Also, for encryption, only the public key is needed.  Digital certificates embed the public key
    //  within the X.509 format itself.  Therefore, if you have a certificate, you also have the public key.
    CkCert cert = new CkCert();
    boolean success = cert.LoadFromFile("qa_data/certs/testCert.cer");
    if (success != true) {
        Log.i(TAG, cert.lastErrorText());
        return;
        }

    success = crypt.SetEncryptCert(cert);
    if (success != true) {
        Log.i(TAG, crypt.lastErrorText());
        return;
        }

    //  Indicate the underlying bulk encryption algorithm to be used:
    crypt.put_Pkcs7CryptAlg("aes");
    crypt.put_KeyLength(128);

    //  Note: When doing public-key encryption the underlying bulk symmetric cipher mode will always be CBC. (at least with Chilkat...)

    //  There's one last option that could be set.  If is the RSA encryption encryption/padding scheme.
    //  By default, RSAES_PKCS1-V1_5 is used.  If desired, the OaepPadding property could be set to true to
    //  use RSAES_OAEP.  (We'll leave it set at the default value of false)
    crypt.put_OaepPadding(false);

    //  Everything is specified.  Now just encrypt...
    //  The output is PKCS7 in binary DER format.
    success = crypt.CkEncryptFile("qa_data/hamlet.xml","qa_output/hamlet.p7");
    if (success != true) {
        Log.i(TAG, crypt.lastErrorText());
        return;
        }

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

  }

  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."
  }
}