Android™

Verify a .p7m and get Algorithm Information

See more Digital Signatures Examples

Demonstrates how to verify a .p7m and then examine the algorithms used by the signature. 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 requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    CkCrypt2 crypt = new CkCrypt2();

    String inFile = "qa_data/p7m/brainpoolP256r1.p7m";
    String outFile = "qa_output/something.dat";

    //  Verify and extract the signed data.
    success = crypt.VerifyP7M(inFile,outFile);
    if (success == false) {
        Log.i(TAG, crypt.lastErrorText());
        return;
        }

    //  Examine details about the signature(s)
    CkJsonObject json = new CkJsonObject();
    crypt.GetLastJsonData(json);
    json.put_EmitCompact(false);
    Log.i(TAG, json.emit());

    //  Sample output

    //  {
    //    "pkcs7": {
    //      "verify": {
    //        "digestAlgorithms": [
    //          "sha256"
    //        ],
    //        "signerInfo": [
    //          {
    //            "cert": {
    //              "serialNumber": "FFFFE552B302FFFFFF1E34C3ACEB2FFFF",
    //              "issuerCN": "The common name of the cert...",
    //              "issuerDN": "",
    //              "digestAlgOid": "2.16.840.1.101.3.4.2.1",
    //              "digestAlgName": "SHA256"
    //            },
    //            "contentType": "1.2.840.113549.1.7.1",
    //            "signingTime": "190409140500Z",
    //            "messageDigest": "lQe9If7vZKFf/NlSYu5Esmlw3phVK/RFsbbb1uH73t8=",
    //            "signingAlgOid": "1.2.840.10045.4.3.2",
    //            "signerDigest": "lQe9If7vZKFf/NlSYu5Esmlw3phVK/RFsbbb1uH73t8=",
    //            "authAttr": [
    //              {
    //                "oid": "1.2.840.113549.1.9.3",
    //                "oidName": "contentType"
    //              },
    //              {
    //                "oid": "1.2.840.113549.1.9.5",
    //                "oidName": "signingTime"
    //              },
    //              {
    //                "oid": "1.2.840.113549.1.9.52",
    //                "oidName": "1.2.840.113549.1.9.52",
    //                "der": "MBs ... AwI="
    //              },
    //              {
    //                "oid": "1.2.840.113549.1.9.4",
    //                "oidName": "messageDigest"
    //              },
    //              {
    //                "oid": "1.2.840.113549.1.9.16.2.47",
    //                "oidName": "signingCertificateV2",
    //                "der": "MCYw .. 7PlQ=="
    //              },
    //              {
    //                "oid": "1.2.840.113549.1.9.20",
    //                "oidName": "1.2.840.113549.1.9.20"
    //              }
    //            ]
    //          }
    //        ]
    //      }
    //    }
    //  }

    //  Code for parsing the above JSON...
    int i;
    int count_i;
    String strVal;
    String certSerialNumber;
    String certIssuerCN;
    String certIssuerDN;
    String certDigestAlgOid;
    String certDigestAlgName;
    String contentType;
    String signingTime;
    String messageDigest;
    String signingAlgOid;
    String signerDigest;
    int j;
    int count_j;
    String oid;
    String oidName;
    String der;

    i = 0;
    count_i = json.SizeOfArray("pkcs7.verify.digestAlgorithms");
    while (i < count_i) {
        json.put_I(i);
        strVal = json.stringOf("pkcs7.verify.digestAlgorithms[i]");
        i = i + 1;
        }

    i = 0;
    count_i = json.SizeOfArray("pkcs7.verify.signerInfo");
    while (i < count_i) {
        json.put_I(i);
        certSerialNumber = json.stringOf("pkcs7.verify.signerInfo[i].cert.serialNumber");
        certIssuerCN = json.stringOf("pkcs7.verify.signerInfo[i].cert.issuerCN");
        certIssuerDN = json.stringOf("pkcs7.verify.signerInfo[i].cert.issuerDN");
        certDigestAlgOid = json.stringOf("pkcs7.verify.signerInfo[i].cert.digestAlgOid");
        certDigestAlgName = json.stringOf("pkcs7.verify.signerInfo[i].cert.digestAlgName");
        contentType = json.stringOf("pkcs7.verify.signerInfo[i].contentType");
        signingTime = json.stringOf("pkcs7.verify.signerInfo[i].signingTime");
        messageDigest = json.stringOf("pkcs7.verify.signerInfo[i].messageDigest");
        signingAlgOid = json.stringOf("pkcs7.verify.signerInfo[i].signingAlgOid");
        signerDigest = json.stringOf("pkcs7.verify.signerInfo[i].signerDigest");
        j = 0;
        count_j = json.SizeOfArray("pkcs7.verify.signerInfo[i].authAttr");
        while (j < count_j) {
            json.put_J(j);
            oid = json.stringOf("pkcs7.verify.signerInfo[i].authAttr[j].oid");
            oidName = json.stringOf("pkcs7.verify.signerInfo[i].authAttr[j].oidName");
            der = json.stringOf("pkcs7.verify.signerInfo[i].authAttr[j].der");
            j = j + 1;
            }

        i = i + 1;
        }

    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."
  }
}