(JavaScript) Get Public Key from CSR

Demonstrates how to get the public key from a CSR.

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

var pem = new CkPem();

// No password is required.  Pass an empty password string..
var noPassword = "";
success = pem.LoadPemFile("qa_data/csr/csr2.pem",noPassword);
if (success !== true) {
    console.log(pem.LastErrorText);
    return;
}

var strBase64 = pem.GetEncodedItem("csr","","base64",0);

var asn = new CkAsn();
success = asn.LoadEncoded(strBase64,"base64");
if (success !== true) {
    console.log(asn.LastErrorText);
    return;
}

// Convert the ASN.1 to XML.
var xml = new CkXml();
success = xml.LoadXml(asn.AsnToXml());
console.log(xml.GetXml());
console.log("----");

var strModulusHex = xml.GetChildContent("bits");
console.log("strModulusHex = " + strModulusHex);
console.log("----");

// We need the modulus as base64.
var bd = new CkBinData();
bd.AppendEncoded(strModulusHex,"hex");
var modulus64 = bd.GetEncoded("base64");
console.log("modulus64 = " + modulus64);
console.log("----");

// Build the XML for the public key.
var xmlPubKey = new CkXml();
xmlPubKey.Tag = "RSAPublicKey";
xmlPubKey.UpdateChildContent("Modulus",modulus64);
// The RSA exponent will always be decimal 65537 (base64 = AQAB)
xmlPubKey.UpdateChildContent("Exponent","AQAB");

console.log("RSA public key as XML:");
console.log(xmlPubKey.GetXml());
console.log("----");

// Load the XML into a Chilkat public key object.
var pubkey = new CkPublicKey();
success = pubkey.LoadFromString(xmlPubKey.GetXml());
if (success !== true) {
    console.log(pubkey.LastErrorText);
    return;
}

// Show the public key as PEM.
var preferPkcs1 = true;
console.log(pubkey.GetPem(preferPkcs1));