Android™

Duplicate openssl dgst -md5 -sign myKey.pem something.txt | openssl enc -base64 -A

See more RSA Examples

Demonstrates how to duplicate the creation of an RSA signature produced by this OpenSSL command:

openssl dgst -md5 -sign myKey.pem something.txt | openssl enc -base64 -A

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

    CkPrivateKey pkey = new CkPrivateKey();

    // Load the private key from an RSA PEM file:
    success = pkey.LoadPemFile("myKey.pem");

    CkRsa rsa = new CkRsa();

    // Import the private key into the RSA component:
    success = rsa.UsePrivateKey(pkey);
    if (success == false) {
        Log.i(TAG, rsa.lastErrorText());
        return;
        }

    // OpenSSL uses BigEndian byte ordering:
    rsa.put_LittleEndian(false);

    // The resulting signature will be a Base64 string:
    rsa.put_EncodingMode("base64");

    // For simplicity, we're not loading
    // the data to be signed from a file.  We are instead simply
    // using a literal string value.  
    String strData = "This is the text to be signed.";

    // Hash the input using MD5, and then sign the hash:
    // Other valid hash algorithm choices are "md2" and "sha-1".
    String base64Sig = rsa.signStringENC(strData,"md5");

    Log.i(TAG, base64Sig);

    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."
  }
}