Java Requires Chilkat v11.0.0+

Verify Opaque Signature and Retrieve Signing Certificates

See more Digital Signatures Examples

Demonstrates how to verify a PCKS7 opaque digital signature (signed data), extract the original file/data, and then extract the certificate(s) that were used to sign. Chilkat2 Java

import com.chilkatsoft.chilkat2.BinData;
import com.chilkatsoft.chilkat2.Cert;
import com.chilkatsoft.chilkat2.CertChain;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Crypt2;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example assumes the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        Crypt2 crypt = new Crypt2();

        // Verify a PKCS7 signed-data (opaque signature) file and extract the original content to a file.
        try {
            crypt.verifyP7M("qa_data/p7m/opaqueSig.p7", "qa_output/originalData.dat");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Alternatively, we can do it in memory...
        BinData binData = new BinData();
        binData.loadFile("qa_data/p7m/opaqueSig.p7");
        // Your app should check for success, but we'll skip the check for brevity..

        // If verified, the signature is unwrapped and binData is replaced with the original data that was signed.
        try {
            crypt.opaqueVerifyBd(binData);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // For our testing, we signed some text, so we can get it from the binData..
        System.out.println("Original Data:");
        System.out.println(binData.getString("utf-8"));

        // After any method call that verifies a signature, the crypt object will contain the certificate(s)
        // that were used for signing (assuming the X.509 certs were available in the signature, which is typically the case).

        // Get each signing certificate, and build the certificate chain for each.
        Cert cert = new Cert();
        CertChain certChain = new CertChain();
        int numCerts = crypt.getNumSignerCerts();
        int i = 0;
        while (i < numCerts) {
            crypt.lastSignerCert(i, cert);
            System.out.println(cert.getSubjectDN());

            try {
                cert.buildCertChain(certChain);
            } catch (ChilkatException e) {
                System.out.println(e.getLastErrorText());
                return;
            }

            i = i + 1;
        }
    }
}