(Node.js) RSA Encrypt and Decrypt Strings

Node.js sample code to RSA public-key encrypt and decrypt strings using public and private keys.

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 rsa = new chilkat.Rsa();

    // This example also generates the public and private
    // keys to be used in the RSA encryption.
    // Normally, you would generate a key pair once,
    // and distribute the public key to your partner.
    // Anything encrypted with the public key can be
    // decrypted with the private key.  The reverse is 
    // also true: anything encrypted using the private
    // key can be decrypted using the public key.

    // Generate a 1024-bit key.  Chilkat RSA supports
    // key sizes ranging from 512 bits to 4096 bits.
    var success = rsa.GenerateKey(1024);
    if (success !== true) {
        console.log(rsa.LastErrorText);
        return;
    }

    // Keys are exported in XML format:
    var publicKey = rsa.ExportPublicKey();
    var privateKey = rsa.ExportPrivateKey();

    var plainText = "Encrypting and decrypting should be easy!";

    // Start with a new RSA object to demonstrate that all we
    // need are the keys previously exported:
    var rsaEncryptor = new chilkat.Rsa();

    // Encrypted output is always binary.  In this case, we want
    // to encode the encrypted bytes in a printable string.
    // Our choices are "hex", "base64", "url", "quoted-printable".
    rsaEncryptor.EncodingMode = "hex";

    // We'll encrypt with the public key and decrypt with the private
    // key.  It's also possible to do the reverse.
    success = rsaEncryptor.ImportPublicKey(publicKey);

    var usePrivateKey = false;
    var encryptedStr = rsaEncryptor.EncryptStringENC(plainText,usePrivateKey);
    console.log(encryptedStr);

    // Now decrypt:
    var rsaDecryptor = new chilkat.Rsa();

    rsaDecryptor.EncodingMode = "hex";
    success = rsaDecryptor.ImportPrivateKey(privateKey);

    usePrivateKey = true;
    var decryptedStr = rsaDecryptor.DecryptStringENC(encryptedStr,usePrivateKey);

    console.log(decryptedStr);

}

chilkatExample();