(Node.js) Get Ed25519 Key in Different Formats

Demonstrates how to get/save an Ed25519 private key to different formats.

Converting a private key from one format to another is done by loading in one format and saving/getting in another.

Note: This example requires Chilkat v9.5.0.83 or greater.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

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

    var eddsa = new chilkat.EdDSA();
    var prng = new chilkat.Prng();
    var privKey = new chilkat.PrivateKey();

    // Generates a new ed25519 key and stores it in privKey.
    var success = eddsa.GenEd25519Key(prng,privKey);
    if (success == false) {
        console.log(eddsa.LastErrorText);
        return;
    }

    // ----------------------------------------------------------
    // Ed25519 PKCS1 format
    // 
    // This is the format created by:  openssl genpkey -algorithm X25519 -out xkey.pem
    var pkcs1Base64 = privKey.GetPkcs1ENC("base64");
    console.log(pkcs1Base64);

    // Sample output:  MC4CAQAwBQYDK2VuBCIEIB1mwirs+eC6XGbkjPIiZyBwQ7768uSd9v5PHOLFbIXo

    // PKCS1 is a binary ASN.1 DER format.  You can examine the contents with two online tools:
    // 1) Go to ASN.1 Decoder  and paste the base64 into the online form.
    // 2) Or Decode Base64 ASN.1 to XML 

    // The PKCS1 ASN.1 format for an Ed25519 key look like this:
    //   SEQUENCE
    //     INTEGER 0
    //     SEQUENCE
    //       OBJECT IDENTIFIER 1.3.101.110 curveX25519 (ECDH 25519 key agreement algorithm)
    //     OCTET STRING 
    //       OCTET STRING (32 byte) 1D66C...

    // Save it directly to a file.
    success = privKey.SavePkcs1File("qa_output/ed25519.key");

    // ----------------------------------------------------------
    // Ed25519 Unencrypted PKCS8 format
    // 
    // For ed25519, the ASN.1 output is the same as for PKCS1.
    var pkcs8Base64 = privKey.GetPkcs8ENC("base64");
    console.log(pkcs8Base64);

    // PKCS8 is a binary ASN.1 DER format.  You can examine the contents with two online tools:
    // 1) Go to ASN.1 Decoder  and paste the base64 into the online form.
    // 2) Or Decode Base64 ASN.1 to XML 

    // ----------------------------------------------------------
    // Ed25519 Encrypted PKCS8 format
    // 
    // Note: The encrypted output cannot be examined using the above online tools because the ASN.1 is encrypted.
    var password = "secret";
    var pkcs8EncBase64 = privKey.GetPkcs8EncryptedENC("base64",password);
    console.log(pkcs8EncBase64);

    // ----------------------------------------------------------
    // Ed25519 in PEM format:
    // 
    var ed25519Pem = privKey.GetPkcs1Pem();
    console.log(ed25519Pem);

    // Sample output:

    // -----BEGIN PRIVATE KEY-----
    // MC4CAQAwBQYDK2VuBCIEIOKPhbULJagBAi7hbRdn1f4AAzh1RqqCHqCAvau7N6yO
    // -----END PRIVATE KEY-----

    // ----------------------------------------------------------
    // Ed25519 in JWK Format
    // 
    var jwk = privKey.GetJwk();

    var json = new chilkat.JsonObject();
    json.Load(jwk);
    json.EmitCompact = false;
    console.log(json.Emit());

    // Sample output:
    // {
    //   "kty": "OKP",
    //   "crv": "Ed25519",
    //   "x": "SE2Kne5xt51z1eciMH2T2ftDQp96Gl6FhY6zSQujiP0",
    //   "d": "O-eRXewadF0sNyB0U9omcnt8Qg2ZmeK3WSXPYgqe570",
    //   "use": "sig"
    // }

    // In the above JWK, x is the public key, y is the private key.
    // Both are 32 bytes and are base64-url encoded.

    // ----------------------------------------------------------
    // Ed25519 in XML Format
    // 
    var ed25519_xml = privKey.GetXml();
    console.log(ed25519_xml);

    // Sample output:  <Ed25519KeyValue>w4b/gI0zgYKgjtfWLjNfc4issmP7Qap84uesYNgEefP/WoY3jNOhOzgTYsMtOnuyGn3MdA4NZtsUXVNI1NiTlA==</Ed25519KeyValue>

    // The base64 content is composed of the concatenation of the 32-byte private key with the 32-byte public key and then base64 encoded.
    // In other words:  Base64(privKey || pubKey)

    // ----------------------------------------------------------
    // Ed25519 in Raw Hex Format
    // 
    var sbPubKeyHex = new chilkat.StringBuilder();
    var privKeyHex = privKey.GetRawHex(sbPubKeyHex);

    // We should have a 32-byte private key (a 64 character hex string).
    console.log("private key = " + privKeyHex);

    // We should have a 32-byte public key (a 64 character hex string).
    console.log("public key = " + sbPubKeyHex.GetAsString());

    // Sample output:
    // key type = ed25519
    // size in bits = 256
    // private key = d4ee72dbf913584ad5b6d8f1f769f8ad3afe7c28cbf1d4fbe097a88f44755842
    // public key = 19bf44096984cdfe8541bac167dc3b96c85086aa30b6b6cb0c5c38ad703166e1

}

chilkatExample();