Android™

RSA Sign String using Private Key of Certificate Type A3 (smart card / token)

See more RSA Examples

Demonstrates RSA signing a string using the private key of a certificate type A3 (smart card, token).

Note: This is a Windows-only example.

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;

    //  First get the A3 certificate that was installed on the Windows system.
    CkCertStore certStore = new CkCertStore();

    String thumbprint = "12c1dd8015f3f03f7b1fa619dc24e2493ca8b4b2";

    //  This is specific to Windows because it is opening the Windows Current-User certificate store.
    boolean bReadOnly = true;
    success = certStore.OpenCurrentUserStore(bReadOnly);
    if (success != true) {
        Log.i(TAG, certStore.lastErrorText());
        return;
        }

    //  Find the certificate with the desired thumbprint
    //  (There are many ways to locate a certificate.  This example chooses to find by thumbprint.)
    CkJsonObject json = new CkJsonObject();
    json.UpdateString("thumbprint",thumbprint);

    CkCert cert = new CkCert();
    success = certStore.FindCert(json,cert);
    if (success == false) {
        Log.i(TAG, "Failed to find the certificate.");
        return;
        }

    Log.i(TAG, "Found: " + cert.subjectCN());

    CkRsa rsa = new CkRsa();

    //  Provide the cert's private key
    boolean bUsePrivateKey = true;
    success = rsa.SetX509Cert(cert,bUsePrivateKey);
    if (success != true) {
        Log.i(TAG, rsa.lastErrorText());
        return;
        }

    //  Return the RSA signature in base64 encoded form.
    rsa.put_EncodingMode("base64");

    //  Sign the utf-8 byte representation of the string.
    rsa.put_Charset("utf-8");

    //  You can also choose other hash algorithms, such as SHA-1.
    String sigBase64 = rsa.signStringENC("text to sign","SHA-256");
    if (rsa.get_LastMethodSuccess() != true) {
        Log.i(TAG, rsa.lastErrorText());
        return;
        }

    Log.i(TAG, "Base64 signature: " + sigBase64);

  }

  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."
  }
}