JavaScript

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. JavaScript

var success = false;

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

var privKey = new CkPrivateKey();

// 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 CkRsa();

// 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 CkCert();

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

var pubKey = new CkPublicKey();
cert.GetPublicKey(pubKey);

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

// 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.");