Node.js

A3/A4 Certificate to Create and Verify an Opaque PKCS7/CMS Signature

See more Digital Signatures Examples

Demonstrates how to use an A3 or A4 certificate w/ private key on a smartcard or token to create a PKCS7 opaque signature, and also how to verify an opaque signature.

An opaque signature is different than a detached PKCS7 signature in that it contains the original data. Verifying an opaque signature retrieves the original content.

Node.js

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

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

    var crypt = new chilkat.Crypt2();

    //  A certificate and private key is needed to create a signature.
    //  Chilkat provides many different ways to load a certificate and private key, such
    //  as from a smartcards and hardware tokens, PFX/.p12, Java keystore, JWK, Windows registry-based certificate stores, and other sources.
    //  This example will load the default certificate from the smartcard that is currently in
    //  the smartcard reader.

    var cert = new chilkat.Cert();

    //  If the smartcard or token requires a PIN, we can set it here to avoid the dialog...
    cert.SmartCardPin = "000000";

    success = cert.LoadFromSmartcard("");
    if (success !== true) {
        console.log(cert.LastErrorText);
        return;
    }

    //  Tell it to use the cert and private key we've loaded.
    success = crypt.SetSigningCert(cert);
    if (success !== true) {
        console.log(crypt.LastErrorText);
        return;
    }

    //  Indicate we want the opaque signature in base64 format:
    crypt.EncodingMode = "base64";

    //  Sign the string using the "utf-8" byte representation:
    crypt.Charset = "utf-8";

    //  Create the opaque signature:
    var originalData = "This is the string to be signed.";
    var opaqueSig = crypt.OpaqueSignStringENC(originalData);
    if (crypt.LastMethodSuccess !== true) {
        console.log(crypt.LastErrorText);
        return;
    }

    console.log(opaqueSig);

    //  The output looks like this:
    //  MIIPgQYJKoZIhvcNAQcCoIIPcjCCD24CAQExCzAJBgUrDgMCGgUAMC8GCSqGSIb3DQEHAaAiBCBUaGlzIGlzIHRoZSBzdHJpbmcgdG8gYmUgc...

    //  ----------------------------------------------------------------------------------------------
    //  Now let's verify the signature and retrieve the original data.
    //  We'll use a new Crypt2 object to keep things completely separate...

    var vCrypt = new chilkat.Crypt2();

    //  We only need the certificate to verify a signature (and extract the data from
    //  an opaque signature).  The public key is always embedded within a certificate.
    success = vCrypt.SetVerifyCert(cert);
    if (success !== true) {
        console.log(vCrypt.LastErrorText);
        return;
    }

    vCrypt.EncodingMode = "base64";
    vCrypt.Charset = "utf-8";

    var extractedData = vCrypt.OpaqueVerifyStringENC(opaqueSig);
    if (vCrypt.LastMethodSuccess !== true) {
        console.log(vCrypt.LastErrorText);
        return;
    }

    console.log("The extracted data: " + extractedData);

    //  The output is:
    //  The extracted data: This is the string to be signed.

}

chilkatExample();