(Android™) PKCS11 XML Signature using Certificate and Private Key on Smart Card / USB Token

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Sample code showing how to use PKCS11 to create an XML digital signature with a certificate and private key stored on a smart card or USB token.

Note: This example requires Chilkat v9.5.0.96 or later.

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// 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.

    // Note: Chilkat's PKCS11 implementation runs on Windows, Linux, Mac OS X, and other supported operating systems.

    CkPkcs11 pkcs11 = new CkPkcs11();

    // This example is tested on Windows using a Giesecke and Devrient Sm@rtCafe Expert 3.2 smart card.
    // You will use the DLL (or shared lib) provided by your smart card vendor, or a DLL compatible with your smart card.
    // On Windows, if the DLL is located in C:\Windows\System32, specify only the filename.
    // Otherwise provide the full path.
    pkcs11.put_SharedLibPath("aetpkss1.dll");

    // Make it an authenticated session by calling Login.
    int userType = 1;
    // Make sure to use the correct PIN for your smart card..
    String pin = "0000";

    boolean success = pkcs11.QuickSession(userType,pin);
    if (success == false) {
        Log.i(TAG, pkcs11.lastErrorText());
        return;
        }

    // Get the certificate (on the smart card) that has a private key.
    CkCert cert = new CkCert();
    success = pkcs11.FindCert("privateKey","",cert);
    if (success == true) {
        Log.i(TAG, "Cert with private key: " + cert.subjectCN());
        }
    else {
        Log.i(TAG, "No certificates having a private key were found.");
        success = pkcs11.CloseSession();
        return;
        }

    // --------------------------------------------------------------------------
    // At this point, we have the cert to be used for signing.
    // Our XML signing code is the same as for a cert obtained from any other source..

    // First generate the following XML to be signed:
    // Use this online tool to generate code from sample XML: 
    // Generate Code to Create XML

    // <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
    // <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
    //     <SOAP-ENV:Header>
    //         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1"></wsse:Security>
    //     </SOAP-ENV:Header>
    //     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
    //         <z:FooBar xmlns:z="http://example.com" />
    //     </SOAP-ENV:Body>
    // </SOAP-ENV:Envelope>

    CkXml xml = new CkXml();
    xml.put_Tag("SOAP-ENV:Envelope");
    xml.AddAttribute("xmlns:SOAP-ENV","http://schemas.xmlsoap.org/soap/envelope/");
    xml.UpdateAttrAt("SOAP-ENV:Header|wsse:Security",true,"xmlns:wsse","http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd");
    xml.UpdateAttrAt("SOAP-ENV:Header|wsse:Security",true,"SOAP-ENV:mustUnderstand","1");
    xml.UpdateAttrAt("SOAP-ENV:Body",true,"xmlns:SOAP-SEC","http://schemas.xmlsoap.org/soap/security/2000-12");
    xml.UpdateAttrAt("SOAP-ENV:Body",true,"SOAP-SEC:id","Body");
    xml.UpdateAttrAt("SOAP-ENV:Body|z:FooBar",true,"xmlns:z","http://example.com");

    CkXmlDSigGen gen = new CkXmlDSigGen();

    // Indicate where the Signature will be inserted.
    gen.put_SigLocation("SOAP-ENV:Envelope|SOAP-ENV:Header|wsse:Security");

    // Add a reference to the fragment of the XML to be signed.

    // Note: "Body" refers to the XML element having an "id" equal to "Body", where "id" is case insensitive
    // and where any namespace might qualify the attribute.  In this case, the SOAP-ENV:Body fragment is signed
    // NOT because the tag = "Body", but because it has SOAP-SEC:id="Body"
    gen.AddSameDocRef("Body","sha1","EXCL_C14N","","");

    // (You can read about the SignedInfoPrefixList in the online reference documentation.  It's optional..)
    gen.put_SignedInfoPrefixList("wsse SOAP-ENV");

    // Provide the private key for signing via the certificate, and indicate that
    // we want the base64 of the certificate embedded in the KeyInfo.
    gen.put_KeyInfoType("X509Data");
    gen.put_X509Type("Certificate");

    boolean bUsePrivateKey = true;
    success = gen.SetX509Cert(cert,bUsePrivateKey);
    if (success != true) {
        Log.i(TAG, gen.lastErrorText());
        success = pkcs11.CloseSession();
        return;
        }

    // Everything's specified.  Now create and insert the Signature
    CkStringBuilder sbXml = new CkStringBuilder();
    xml.put_EmitCompact(true);
    xml.GetXmlSb(sbXml);

    success = gen.CreateXmlDSigSb(sbXml);
    if (success != true) {
        Log.i(TAG, gen.lastErrorText());
        success = pkcs11.CloseSession();
        return;
        }

    // Examine the XML with the digital signature inserted
    Log.i(TAG, sbXml.getAsString());

    // --------------------------------------------------------------------------

    // Revert to an unauthenticated session by calling Logout.
    success = pkcs11.Logout();
    if (success == false) {
        Log.i(TAG, pkcs11.lastErrorText());
        success = pkcs11.CloseSession();
        return;
        }

    // When finished, close the session.
    // It is important to close the session (memory leaks will occur if the session is not properly closed).
    success = pkcs11.CloseSession();
    if (success == false) {
        Log.i(TAG, pkcs11.lastErrorText());
        return;
        }

    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."
  }
}