JavaScript

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

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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.

JavaScript

var success = false;

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

var crypt = new CkCrypt2();

// 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 CkCert();

// 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 CkCrypt2();

// 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.