Node.js

About RSA Public/Private Keys

See more RSA Examples

This example provides some additional information for understanding public/private key pairs. In demonstrates how a private key is a superset of the public key. A public key contains the modulus and exponent. The matching private key also contains the modulus and exponent, but also contains the additional private key parts. Node.js

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

    var cert = new chilkat.Cert();

    // Load a digital certificate.
    success = cert.LoadFromFile("digitalCert.cer");
    if (success == false) {
        console.log(cert.LastErrorText);
        return;
    }

    // A .cer file does not contain the private key.  It should contain
    // the public key...
    var pubKey = new chilkat.PublicKey();
    cert.GetPublicKey(pubKey);

    // Let's have a look at it (in XML format).
    console.log("Public Key from Certificate:");
    console.log(pubKey.GetXml());

    // An RSA public key consists of a modulus and exponent.

    // An RSA private key includes both the modulus and exponent,
    // as well as other "big" numbers: P, Q, D, etc.

    // Let's load an RSA private key from a DER-encoded file:
    var privKey = new chilkat.PrivateKey();

    success = privKey.LoadAnyFormatFile("PrivateKey.key","");
    if (success !== true) {
        console.log(privKey.LastErrorText);
        return;
    }

    // If this private key is the matching half to the public key from
    // the certificate, then the modulus and exponent should
    // be identical.  (Thus, a "private key" really contains both the public part as well as the private parts...).
    console.log("Private Key from DER:");
    console.log(privKey.GetXml());

}

chilkatExample();