Node.js

RSA Signature/Verify with .key and .cer

See more RSA Examples

Demonstrates how to use a .key file (private key) and digital certificate (.cer, public key) to create and verify an RSA signature. 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 privKey = new chilkat.PrivateKey();

    // Load the private key from an RSA .key file:
    success = privKey.LoadPemFile("privateKey.key");
    if (success == false) {
        console.log(privKey.LastErrorText);
        return;
    }

    var rsa = new chilkat.Rsa();

    // Import the private key into the RSA component:
    success = rsa.UsePrivateKey(privKey);
    if (success == false) {
        console.log(rsa.LastErrorText);
        return;
    }

    // Create the signature as a hex string:
    rsa.EncodingMode = "hex";

    var strData = "This is the string to be signed.";

    // Sign the string using the sha256 hash algorithm.
    // Other valid choices are "md2", "sha1", "sha384",
    // "sha512", and "md5".
    var hexSig = rsa.SignStringENC(strData,"sha256");

    console.log(hexSig);

    // Load a digital certificate from a .cer file:
    var cert = new chilkat.Cert();

    success = cert.LoadFromFile("myCert.cer");
    if (success == false) {
        console.log(cert.LastErrorText);
        return;
    }

    var pubKey = new chilkat.PublicKey();
    cert.GetPublicKey(pubKey);

    // Now verify using a new instance of the RSA object:
    var rsa2 = new chilkat.Rsa();

    // Import the public key into the RSA object:
    success = rsa2.UsePublicKey(pubKey);
    if (success == false) {
        console.log(rsa2.LastErrorText);
        return;
    }

    // The signature is a hex string, so make sure the EncodingMode is correct:
    rsa2.EncodingMode = "hex";

    // Verify the signature:
    success = rsa2.VerifyStringENC(strData,"sha256",hexSig);
    if (success == false) {
        console.log(rsa2.LastErrorText);
        return;
    }

    console.log("Success.");

}

chilkatExample();