(Android™) Duplicate PHP RSA Encryption

Demonstrates how to duplicate the following PHP function.

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.

    // Duplicate the following PHP code:
    // 
    //    public function encryptRSA($plainText,$rsaMOD,$pubKEY){
    //         $rsa  = new RSA();
    //         $rsa->setEncryptionMode(RSA::ENCRYPTION_PKCS1);
    //         $publicKey = [
    //             'e' => new BigInteger($pubKEY,16),
    //             'n' => new BigInteger($rsaMOD,16)
    //         ];
    // 		
    //         $rsa->loadKey($publicKey);
    //         $ciphertext = $rsa->encrypt($plainText);
    //         return bin2hex($ciphertext);
    //     }
    // 
    //     $plainText="key=abcdefghijkmnopq&iv=abcdefghijkmnopq&h=12345678&s=12345678"
    //     $rsaMOD="F0946D8F05604809E24B8CFFD30349CEA9E5F4D320BFD9E9AA1B088863F02C43E7997D37A3E27B4F8F359F1744DB6B20A437067C0D325A80660D12FF56A57673"
    //     $pubKEY="010001"

    // We have the RSA modulus in hex
    String rsaMOD = "F0946D8F05604809E24B8CFFD30349CEA9E5F4D320BFD9E9AA1B088863F02C43E7997D37A3E27B4F8F359F1744DB6B20A437067C0D325A80660D12FF56A57673";

    // The RSA exponent in hex is "010001", which is 65537 in decimal.  It's typically the exponent that is always used.
    String rsaEXP = "010001";

    // Get the RSA modulus and exponent in base64.
    CkBinData bdMod = new CkBinData();
    CkBinData bdExp = new CkBinData();
    boolean success = bdMod.AppendEncoded(rsaMOD,"hex");
    success = bdExp.AppendEncoded(rsaEXP,"hex");

    // Build the XML representation of the RSA public key
    CkXml xml = new CkXml();
    xml.put_Tag("RSAPublicKey");
    xml.UpdateChildContent("Modulus",bdMod.getEncoded("base64"));
    xml.UpdateChildContent("Exponent",bdExp.getEncoded("base64"));

    // Load the RSA public key into a Chilkat public key object.
    CkPublicKey pubkey = new CkPublicKey();
    success = pubkey.LoadFromString(xml.getXml());

    // Setup the RSA object for encryption and do it..
    CkRsa rsa = new CkRsa();
    rsa.put_VerboseLogging(true);
    success = rsa.ImportPublicKeyObj(pubkey);

    // Use PKCSv1.5 padding
    rsa.put_OaepPadding(false);

    // Encrypt and return the string as hex.
    rsa.put_EncodingMode("hex");
    String plainText = "key=abcdefghijkmnopq&iv=abcdefghijkmnopq&h=12345678&s=12345678";
    String cipherText = rsa.encryptStringENC(plainText,false);
    if (rsa.get_LastMethodSuccess() == false) {
        Log.i(TAG, rsa.lastErrorText());
        return;
        }

    // Note: The PKCSv1_5 padding incorporates random bytes.  Therefore, the RSA encryption will produce different results each time -- all of which are valid 
    // and decrypt correctly to the same original text.
    Log.i(TAG, cipherText);

  }

  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."
  }
}