Android™

Encrypt File using X.509 Certificate using AES in CBC Mode

See more Encryption Examples

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.) 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 requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample 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();
    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."
  }
}