(Android™) Validate Certificate using OCSP Protocol

Demonstrates how to validate a certificate (check the revoked status) using the OCSP protocol.

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);

    // Note: Requires Chilkat v9.5.0.75 or greater.

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

    // This example will check the revoked status of a certificate loaded from a file.
    CkCert cert = new CkCert();
    boolean success = cert.LoadFromFile("qa_data/certs/google.crt");
    if (success != true) {
        Log.i(TAG, cert.lastErrorText());
        return;
        }

    // Get the cert's OCSP URL.
    String ocspUrl = cert.ocspUrl();

    // Build the JSON that will be the OCSP request.

    // Possible hash algorithms are sha1, sha256, sha384, sha512.  
    String hashAlg = "sha256";
    CkPrng prng = new CkPrng();
    CkJsonObject json = new CkJsonObject();
    json.put_EmitCompact(false);
    // Read more about OCSP nonce lengths
    json.UpdateString("extensions.ocspNonce",prng.genRandom(16,"base64"));
    json.put_I(0);
    json.UpdateString("request[i].cert.hashAlg",hashAlg);
    json.UpdateString("request[i].cert.issuerNameHash",cert.hashOf("IssuerDN",hashAlg,"base64"));
    json.UpdateString("request[i].cert.issuerKeyHash",cert.hashOf("IssuerPublicKey",hashAlg,"base64"));
    json.UpdateString("request[i].cert.serialNumber",cert.serialNumber());

    Log.i(TAG, json.emit());

    // Our OCSP request looks something like this:
    // {
    //   "extensions": {
    //     "ocspNonce": "qZDfbpO+nUxRzz6c/SPjE5QCAsPfpkQlRDxTnGl0gnxt7iXO"
    //   },
    //   "request": [
    //     {
    //       "cert": {
    //         "hashAlg": "sha1",
    //         "issuerNameHash": "9u2wY2IygZo19o11oJ0CShGqbK0=",
    //         "issuerKeyHash": "d8K4UJpndnaxLcKG0IOgfqZ+uks=",
    //         "serialNumber": "6175535D87BF94B6"
    //       }
    //     }
    //   ]
    // }

    CkBinData ocspRequest = new CkBinData();
    CkHttp http = new CkHttp();

    // Convert our JSON to a binary (ASN.1) OCSP request
    success = http.CreateOcspRequest(json,ocspRequest);
    if (success == false) {
        Log.i(TAG, http.lastErrorText());
        return;
        }

    // Send the OCSP request to the OCSP server
    CkHttpResponse resp = http.PBinaryBd("POST",ocspUrl,ocspRequest,"application/ocsp-request",false,false);
    if (http.get_LastMethodSuccess() != true) {
        Log.i(TAG, http.lastErrorText());
        return;
        }

    // Get the binary (ASN.1) OCSP reply
    CkBinData ocspReply = new CkBinData();
    resp.GetBodyBd(ocspReply);

    // Convert the binary reply to JSON.
    // Also returns the overall OCSP response status.
    CkJsonObject jsonReply = new CkJsonObject();
    int ocspStatus = http.ParseOcspReply(ocspReply,jsonReply);

    // The ocspStatus can have one of these values:
    // -1:  The ARG1 does not contain a valid OCSP reply.
    // 0:  Successful - Response has valid confirmations..
    // 1: Malformed request - Illegal confirmation request.
    // 2: Internal error - Internal error in issuer.
    // 3: Try later -  Try again later.
    // 4: Not used - This value is never returned.
    // 5: Sig required - Must sign the request.
    // 6: Unauthorized - Request unauthorized.

    if (ocspStatus < 0) {
        Log.i(TAG, "Invalid OCSP reply.");
        return;
        }

    Log.i(TAG, "Overall OCSP Response Status: " + String.valueOf(ocspStatus));

    // Let's examine the OCSP response (in JSON).
    jsonReply.put_EmitCompact(false);
    Log.i(TAG, jsonReply.emit());

    // The JSON reply looks like this:
    // (Use the online tool at https://tools.chilkat.io/jsonParse.cshtml
    // to generate JSON parsing code.)

    // {
    //   "responseStatus": 0,
    //   "responseTypeOid": "1.3.6.1.5.5.7.48.1.1",
    //   "responseTypeName": "ocspBasic",
    //   "response": {
    //     "responderIdChoice": "KeyHash",
    //     "responderKeyHash": "d8K4UJpndnaxLcKG0IOgfqZ+uks=",
    //     "dateTime": "20180803193937Z",
    //     "cert": [
    //       {
    //         "hashOid": "1.3.14.3.2.26",
    //         "hashAlg": "SHA-1",
    //         "issuerNameHash": "9u2wY2IygZo19o11oJ0CShGqbK0=",
    //         "issuerKeyHash": "d8K4UJpndnaxLcKG0IOgfqZ+uks=",
    //         "serialNumber": "6175535D87BF94B6",
    //         "status": 0,
    //         "thisUpdate": "20180803193937Z",
    //         "nextUpdate": "20180810193937Z"
    //       }
    //     ]
    //   }
    // }
    // 

    // The certificate status:
    int certStatus = -1;
    if (jsonReply.HasMember("response.cert[0].status") == true) {
        certStatus = jsonReply.IntOf("response.cert[0].status");
        }

    // Possible certStatus values are:
    // -1: No status returned.
    // 0: Good
    // 1: Revoked
    // 2: Unknown.
    Log.i(TAG, "Certificate Status: " + String.valueOf(certStatus));

  }

  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."
  }
}