(Node.js) Convert PuTTY Private Key (ppk) to OpenSSH (pem)

Convert a PuTTY format private key file (.ppk) to OpenSSH (.pem).

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() {

    var key = new chilkat.SshKey();

    var success;

    // Load an unencrypted or encrypted PuTTY private key.

    // If  your PuTTY private key is encrypted, set the Password
    // property before calling FromPuttyPrivateKey.
    // If your PuTTY private key is not encrypted, it makes no diffference
    // if Password is set or not set.
    key.Password = "secret";

    // First load the .ppk file into a string:
    var keyStr;
    keyStr = key.LoadText("putty_private_key.ppk");

    // Import into the SSH key object:
    success = key.FromPuttyPrivateKey(keyStr);
    if (success !== true) {
        console.log(key.LastErrorText);
        return;
    }

    // Convert to an encrypted or unencrypted OpenSSH key.

    // First demonstrate converting to an unencrypted OpenSSH key
    var unencryptedKeyStr;
    var bEncrypt = false;
    unencryptedKeyStr = key.ToOpenSshPrivateKey(bEncrypt);
    success = key.SaveText(unencryptedKeyStr,"unencrypted_openssh.pem");
    if (success !== true) {
        console.log(key.LastErrorText);
        return;
    }

    // Save to an encrypted OpenSSH PEM file:
    var encryptedKeyStr;
    bEncrypt = true;
    key.Password = "myPassword";
    encryptedKeyStr = key.ToOpenSshPrivateKey(bEncrypt);
    success = key.SaveText(encryptedKeyStr,"encrypted_openssh.pem");
    if (success !== true) {
        console.log(key.LastErrorText);
        return;
    }

    console.log("Done!");

}

chilkatExample();