(Android™) CAdES BES Attached (Opaque) Signature

Demonstrates how to create a CAdES BES attached signature file (.p7m). This is a PKCS7 signature format (known as an opaque, or "attached" signature) where the file data is embedded within the signature file. The signature verification both verifies the signature and extracts the original data.

(A "detached" signature is where the original data is NOT included within the PKCS7 signature format.)

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

    CkCrypt2 crypt = new CkCrypt2();

    // Use a digital certificate and private key from a PFX file (.pfx or .p12).
    String pfxPath = "qa_data/pfx/myCertAndPrivateKey.p12";
    String pfxPassword = "password";

    CkCert cert = new CkCert();
    boolean success = cert.LoadPfxFile(pfxPath,pfxPassword);
    if (success != true) {
        Log.i(TAG, cert.lastErrorText());
        return;
        }

    // Tell the crypt component to use this cert.
    success = crypt.SetSigningCert(cert);
    if (success != true) {
        Log.i(TAG, crypt.lastErrorText());
        return;
        }

    // The CadesEnabled property applies to all methods that create PKCS7 signatures. 
    // To create a CAdES-BES signature, set this property equal to true. 
    crypt.put_CadesEnabled(true);

    // To sign with SHA1, set the HashAlgorithm property to "sha1"
    crypt.put_HashAlgorithm("sha1");

    // To sign with SHA256, set the HashAlgorithm property to "SHA256".
    crypt.put_HashAlgorithm("sha256");

    // Other hash algorithm choices are "md5", "md2", "sha384", and "sha512"

    // We can sign any type of file, creating a .p7m as output.
    // The .p7m contains the signature and also embeds the data of the file that is signed.
    String inFile = "qa_data/json/sample.json";
    String sigFile = "qa_output/signature.p7m";

    // -----------------------------------------------------------------------------------------
    // Also see Chilkat's online tool to examine a .p7m and generate code to duplicate the .p7m
    // -----------------------------------------------------------------------------------------

    // Create the CAdES-BES attached signature, which contains the original data.
    success = crypt.CreateP7M(inFile,sigFile);
    if (success == false) {
        Log.i(TAG, crypt.lastErrorText());
        return;
        }

    // Verify the .p7m file and extract the original file from the .p7m. 
    String extractedToFilePath = "qa_output/sample.json";
    success = crypt.VerifyP7M(sigFile,extractedToFilePath);
    if (success == false) {
        Log.i(TAG, crypt.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."
  }
}