(Node.js) RSA Sign Binary Data and Verify (Recover the Original Data)

Demonstrates how to RSA sign binary data and then verify/recover the original data.

Note: This example uses methods introduced in Chilkat v9.5.0.77.

Note: This example requires Chilkat v11.0.0 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, MacOS

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-mac-universal');
}

function chilkatExample() {

    var success = false;

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

    // Load an RSA private key for signing.
    var privKey = new chilkat.PrivateKey();
    success = privKey.LoadEncryptedPemFile("qa_data/pem/rsa_passwd.pem","passwd");
    if (success == false) {
        console.log(privKey.LastErrorText);
        return;
    }

    var rsa = new chilkat.Rsa();
    rsa.UsePrivateKey(privKey);

    // We have some binary data (in hex) to sign
    var originalData = "0102030405060708090A";
    var bd = new chilkat.BinData();
    bd.AppendEncoded(originalData,"hex");

    // If successful, the contents of bd are replaced with the RSA signature.
    success = rsa.SignRawBd(bd);
    if (success == false) {
        console.log(rsa.LastErrorText);
        return;
    }

    // Show the RSA signature in base64
    console.log(bd.GetEncoded("base64"));

    // ------------------------------------------
    // Get the public key from the private key
    var pubKey = new chilkat.PublicKey();
    privKey.ToPublicKey(pubKey);

    // Verify the signature and extract the original data.
    var rsa2 = new chilkat.Rsa();
    rsa2.UsePublicKey(pubKey);

    var bVerified = rsa2.VerifyRawBd(bd);
    console.log("signature verified: " + bVerified);

    // Show the original data:
    console.log("original data: " + bd.GetEncoded("hex"));

}

chilkatExample();