(Node.js) RSA Encrypt String to Encoded Result and Reverse

See more RSA Examples

Demonstrates how to RSA encrypt a string to a base64 encoded result, and the reverse.

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

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-mac-universal');
}

function chilkatExample() {

    // The RSA public key is used for encryption, and the private key for decryption.

    // The public key's role is to make encryption accessible to anyone while ensuring that
    // only the private key holder can decrypt the messages.
    // The public key is designed to be widely distributed so anyone can use it to encrypt messages
    // intended for the owner of the private key.

    // Load our 2048-bit RSA public key.
    var pubKey = new chilkat.PublicKey();
    // In all Chilkat methods expecting a path, you pass either absolute or relative paths.
    var success = pubKey.LoadFromFile("rsaKeys/myTestRsaPublic.pem");
    if (success == false) {
        console.log(pubKey.LastErrorText);
        return;
    }

    var rsa = new chilkat.Rsa();

    // Tell RSA to use the public key.
    rsa.ImportPublicKeyObj(pubKey);

    // RSA encryption is for small amounts of data, on the order of 200 bytes or less.
    // The maximum number of bytes that can be RSA encrypted depends
    // on the RSA key size and padding scheme (OAEP padding vs PKCS#1 v1.5 padding).
    // For specific limits, see: RSA Encryption Maximum Number of Bytes

    // Encrypt the utf-8 byte representation of the string.
    rsa.Charset = "utf-8";
    rsa.EncodingMode = "base64";

    // Be Careful when Using non-us-ascii String Literals in Source Code
    var encryptedB64 = rsa.EncryptStringENC("Élève français dîne à côté d’un café où l’on sert déjà du gâteau au chocolat et des éclairs délicieux",false);

    // ------------------------------------------------------------------------------------------------------------------------
    // Let's decrypt, which requires the matching private key...

    // Load the matching 2048-bit RSA private key.
    var privKey = new chilkat.PrivateKey();
    var password = "secret";
    success = privKey.LoadAnyFormatFile("rsaKeys/myTestRsaPrivate.pem",password);
    if (success == false) {
        console.log(privKey.LastErrorText);
        return;
    }

    // Tell the RSA object to use the private key.
    rsa.ImportPrivateKeyObj(privKey);

    // Indicate that after decrypting the resultant decrypted bytes contains the utf-8 byte representation of the text.
    rsa.Charset = "utf-8";
    rsa.EncodingMode = "base64";
    var originalText = rsa.DecryptStringENC(encryptedB64,true);
    if (success == false) {
        console.log(rsa.LastErrorText);
        return;
    }

    console.log("Original text = " + originalText);
    console.log("Success.");

}

chilkatExample();