(Node.js) Export a Certificate's Private Key to Various Formats

Loads a digital certificate and private key from a PFX file (also known as PKCS#12) and exports the private key to various formats: (1) PKCS8 Encrypted, (2) PKCS8 Encrypted PEM, (3) PKCS8 unencrypted, (4) PKCS8 PEM unencrypted, (5) RSA DER unencrypted, (6) RSA PEM unencrypted, (7) XML.

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 cert = new chilkat.Cert();

    // Load from the PFX file
    var pfxFilename = "/Users/chilkat/testData/pfx/chilkat_ssl_pwd_is_test.pfx";
    var pfxPassword = "test";

    // A PFX typically contains certificates in the chain of authentication.
    // The Chilkat cert object will choose the certificate w/
    // private key farthest from the root authority cert.
    // To access all the certificates in a PFX, use the 
    // Chilkat certificate store object instead.
    var success = cert.LoadPfxFile(pfxFilename,pfxPassword);
    if (success !== true) {
        console.log(cert.LastErrorText);
        return;
    }

    // Get the private key...
    // privKey: PrivateKey
    var privKey;
    privKey = cert.ExportPrivateKey();
    if (cert.LastMethodSuccess == false) {
        console.log(cert.LastErrorText);
        return;
    }

    // Export to various formats:

    var password = "secret";
    var path;

    // PKCS8 Encrypted DER
    path = "/Users/chilkat/testData/privkeys/chilkat_pkcs8_enc.der";
    success = privKey.SavePkcs8EncryptedFile(password,path);
    if (success !== true) {
        console.log(privKey.LastErrorText);

        return;
    }

    // PKCS8 Encrypted PEM
    path = "/Users/chilkat/testData/privkeys/chilkat_pkcs8_enc.pem";
    success = privKey.SavePkcs8EncryptedPemFile(password,path);
    if (success !== true) {
        console.log(privKey.LastErrorText);

        return;
    }

    // PKCS8 Unencrypted DER
    path = "/Users/chilkat/testData/privkeys/chilkat_pkcs8.der";
    success = privKey.SavePkcs8File(path);
    if (success !== true) {
        console.log(privKey.LastErrorText);

        return;
    }

    // PKCS8 Unencrypted PEM
    path = "/Users/chilkat/testData/privkeys/chilkat_pkcs8.pem";
    success = privKey.SavePkcs8PemFile(path);
    if (success !== true) {
        console.log(privKey.LastErrorText);

        return;
    }

    //  RSA DER (unencrypted)
    path = "/Users/chilkat/testData/privkeys/chilkat_rsa.der";
    success = privKey.SavePkcs1File(path);
    if (success !== true) {
        console.log(privKey.LastErrorText);

        return;
    }

    // RSA PEM (unencrypted)
    path = "/Users/chilkat/testData/privkeys/chilkat_rsa.pem";
    success = privKey.SavePemFile(path);
    if (success !== true) {
        console.log(privKey.LastErrorText);

        return;
    }

    // XML (unencrypted)
    path = "/Users/chilkat/testData/privkeys/chilkat.xml";
    success = privKey.SaveXmlFile(path);
    if (success !== true) {
        console.log(privKey.LastErrorText);

        return;
    }

    console.log("Private key exported to all formats.");

}

chilkatExample();