(Node.js) RSASSA-PSS Sign String to Create Base64 PCKS7 Signature

Signs a string to create a PKCS7 signature in the base64 encoding. The signature algorithm is RSASSA-PSS with SHA256.

Note: This example requires Chilkat v9.5.0.67 or greater.

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 requires the Chilkat Crypt API to have been previously unlocked.
    // See Unlock Chilkat Crypt for sample code.

    var crypt = new chilkat.Crypt2();

    // Get a digital certificate with private key from a .pfx
    // (Chilkat has many different ways to provide a cert + private key for siging.
    // Using a PFX is just one possible option.)
    var pfx = new chilkat.Pfx();
    var success = pfx.LoadPfxFile("qa_data/rsassa-pss/privatekey.pfx","PFX_PASSWORD");
    if (success !== true) {
        console.log(pfx.LastErrorText);
        return;
    }

    // Get the certificate to be used for signing.
    // (The typical case for a PFX is that it contains a cert with an associated private key,
    // as well as other certificates in the chain of authentication.  The cert with the private
    // key should be in the first position at index 0.)
    // cert: Cert
    var cert = pfx.GetCert(0);
    if (pfx.LastMethodSuccess !== true) {
        console.log(pfx.LastErrorText);
        return;
    }

    crypt.SetSigningCert(cert);

    // Indicate that RSASSA-PSS with SHA256 should be used.
    crypt.SigningAlg = "pss";
    crypt.HashAlgorithm = "sha256";

    crypt.EncodingMode = "base64";

    // Sign a string and return the base64 PKCS7 detached signature
    var originalText = "This is a test";
    var pkcs7sig = crypt.SignStringENC(originalText);
    console.log("Detached Signature:");
    console.log(pkcs7sig);

    // This signature looks like this:
    // MIIG5wYJKoZIhvcNAQcCoIIG2DCCBtQCAQExDzANBgl .. YToLqEwTdU87ox5g7rvw==

    // The ASN.1 of the signature can be examined by browsing to https://lapo.it/asn1js/ ,
    // then copy-and-paste the Base64 signature into the form and decode..

    // The signature can be verified against the original data like this:
    success = crypt.VerifyStringENC(originalText,pkcs7sig);
    console.log("Signature verified: " + success);
    success = crypt.VerifyStringENC("Not the original text",pkcs7sig);
    console.log("Signature verified: " + success);

    // Now we'll create an opaque signature (the opposite of a detached signature). 
    // An opaque signature is a PKCS7 message that contains both the original data and
    // the signature.  The verification process extracts the original data.
    var opaqueSig = crypt.OpaqueSignStringENC(originalText);
    console.log("Opaque Signature:");
    console.log(opaqueSig);

    // The ASN.1 of the signature can be examined by browsing to https://lapo.it/asn1js/ ,
    // then copy-and-paste the Base64 signature into the form and decode..

    // We can verify and extract the original data:
    var origTxt = crypt.OpaqueVerifyStringENC(opaqueSig);
    if (crypt.LastMethodSuccess !== true) {
        console.log("Signature verification failed.");
        console.log(crypt.LastErrorText);

        return;
    }

    console.log("Signature verified.");
    console.log("Extracted text:" + origTxt);


}

chilkatExample();