(JavaScript) 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.

Note

This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.

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 CkPrivateKey();
success = privKey.LoadEncryptedPemFile("qa_data/pem/rsa_passwd.pem","passwd");
if (success == false) {
    console.log(privKey.LastErrorText);
    return;
}

var rsa = new CkRsa();
rsa.UsePrivateKey(privKey);

// We have some binary data (in hex) to sign
var originalData = "0102030405060708090A";
var bd = new CkBinData();
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 CkPublicKey();
privKey.ToPublicKey(pubKey);

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

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

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