Java

CMS Sign Hash

Demonstrates how to use the SignHashENC method to sign a pre-computed hash. This method creates a CMS signature (PKCS7 detached signature).

This example requires Chilkat v9.5.0.90 or later.

Chilkat2 Java

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

public class ChilkatExample {

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

        Crypt2 crypt = new Crypt2();

        // Create the hash to be signed...
        crypt.setHashAlgorithm("sha256");
        crypt.setEncodingMode("base64");
        crypt.setCharset("utf-8");
        // Create the SHA256 hash of a string using the utf-8 byte representation.
        // Return the hash as base64.
        String base64Hash = crypt.hashStringENC("This is the string to be hashed");

        // Load a certificate for signing.
        Cert cert = new Cert();
        String base64CmsSig;
        try {
            cert.loadPfxFile("qa_data/pfx/cert_test123.pfx", "test123");

            crypt.setSigningCert(cert);

            // Sign the hash to create a base64 CMS signature (which does not contain the original data).
            // We can get the signature in a single line of base64 by specifying "base64", or
            // we can get multi-line base64 by specifying "base64_mime".
            crypt.setEncodingMode("base64_mime");
            base64CmsSig = crypt.signHashENC(base64Hash, "sha256", "base64");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Note: In the above call to SignHashENC, the encoding of the returned CMS signature is specified by the EncodingMode property.
        // However, the encoding of the passed-in hash is indicated by the 3rd argument.

        System.out.println("CMS Signature: " + base64CmsSig);
    }
}