(Android™) Encrypt with Chilkat, Decrypt with OpenSSL

Demonstrates how to RSA encrypt a string using Chilkat, and then shows the corresponding OpenSSL command to RSA decrypt. The OpenSSL command to decrypt is as follows:

openssl rsautl -decrypt -inkey VP_Private.pem -in rsa_encrypted.bin -out original.txt

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 API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkRsa rsa = new CkRsa();

    // Note: RSA encryption uses the public key.  
    // RSA decryption uses the private key.
    // The reason is that the public key can be freely provided to anybody.  This allows anybody
    // to send an encrypted message to the private key owner, and only the private key owner 
    // can decrypt.
    CkPublicKey key = new CkPublicKey();

    // Load an RSA public key from a PEM file:
    boolean success = key.LoadFromFile("qa_data/pem/VP_Public.pem");
    if (success != true) {
        Log.i(TAG, key.lastErrorText());
        return;
        }

    // Load the public key into the RSA object.
    success = rsa.ImportPublicKeyObj(key);
    if (success != true) {
        Log.i(TAG, rsa.lastErrorText());
        return;
        }

    String strToEncrypt = "00000000;XYZ2-3BHQ-ABCD-MMVV;6MY1-GHJK-9LRR;0";

    // The LittleEndian property is false by default, but it is set here
    // anyway to show that LittleEndian byte ordering is required for OpenSSL compatibility.
    rsa.put_LittleEndian(false);

    boolean usePrivateKey = false;
    CkByteData encryptedBytes = new CkByteData();
    success = rsa.EncryptString(strToEncrypt,usePrivateKey,encryptedBytes);
    if (rsa.get_LastMethodSuccess() != true) {
        Log.i(TAG, rsa.lastErrorText());
        return;
        }

    // The OpenSSL command to decrypt would be this:
    // openssl rsautl -decrypt -inkey VP_Private.pem -in rsa_encrypted.bin -out original.txt

    CkFileAccess fac = new CkFileAccess();
    success = fac.WriteEntireFile("qa_output/rsa_encrypted.bin",encryptedBytes);
    if (success != true) {
        Log.i(TAG, fac.lastErrorText());
        return;
        }

    Log.i(TAG, "RSA Encryption Succeeded.");

  }

  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."
  }
}