(Node.js) Create and Verify an Opaque PKCS7/CMS Signature

Demonstrates how 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.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

    // 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 PFX/.p12, Java keystore, JWK, Windows registry-based certificate stores, and other sources.
    // This example will load the certificate from a .crt and the private key from a .key file

    var cert = new chilkat.Cert();
    // The LoadFromFile method will automatically detect the format and load it.
    var success = cert.LoadFromFile("qa_data/certs/test_12345678a.cer");
    if (success !== true) {
        console.log(cert.LastErrorText);
        return;
    }

    // Our private key is in an encrypted PKCS8 format.
    // If you don't know the format of your key, but you do know it's encrypted,
    // and requires a password, then just call any of the Chilkat methods that load
    // a private key w/ a password argument.  Chilkat will auto-detect the format
    // and load it correctly even if it's not the format indicated by the method name..
    var privKey = new chilkat.PrivateKey();
    var password = "12345678a";
    success = privKey.LoadPkcs8EncryptedFile("qa_data/certs/test_12345678a.key",password);
    if (success !== true) {
        console.log(privKey.LastErrorText);
        return;
    }

    // Set properties required for signing.

    // Tell it to use the cert and private key we've loaded.
    success = crypt.SetSigningCert2(cert,privKey);
    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();

    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();