(Node.js) Streaming Encryption

Encrypt and decrypt using a stream.

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 crypt = new chilkat.Crypt2();

    // Setup encryption using the chacha20 algorithm...
    crypt.CryptAlgorithm = "chacha20";
    crypt.KeyLength = 256;
    crypt.EncodingMode = "hex";
    var ivHex = "000000000000000000000002";
    crypt.SetEncodedIV(ivHex,"hex");
    crypt.InitialCount = 42;
    var keyHex = "1c9240a5eb55d38af333888604f6b5f0473917c1402b80099dca5cbc207075c0";
    crypt.SetEncodedKey(keyHex,"hex");

    var plainText = "The quick brown fox jumped over the lazy dog.\r\n";

    var stream = new chilkat.Stream();

    // We'll save the encrypted output in eStrings to demonstrate streaming decryption next.
    var eStrings = new chilkat.StringArray();

    // Start a background task that will encrypt a stream.
    // task: Task
    var task = crypt.EncryptStreamAsync(stream);
    var success = task.Run();

    // Write plainText to the stream, and read chacha20 encrypted text..
    var cipherText;
    var i;
    for (i = 1; i <= 10; i++) {
        // Note: An encryption algorithm's block size will cause buffering,
        // and therefore not every loop iteration will produce output.
        success = stream.WriteString(plainText);
        if (stream.DataAvailable == true) {
            cipherText = stream.ReadBytesENC("hex");
            console.log(cipherText);
            success = eStrings.Append(cipherText);
        }

    }

    // Tell the background task that the stream has ended.
    success = stream.WriteClose();

    // Let's make sure the background task finished.
    // It should already be the case that the task is finished.
    while ((task.Finished !== true)) {
        task.SleepMs(20);
    }

    // Get any remaining data available from the stream.
    if (stream.DataAvailable == true) {
        cipherText = stream.ReadBytesENC("hex");
        console.log(cipherText);
        success = eStrings.Append(cipherText);
    }

    if (task.TaskSuccess !== true) {
        console.log("async encryption failed:");
        console.log(task.ResultErrorText);
        success = false;
    }

    console.log("-- encrypt finished --");

    // Now decrypt to return the original.

    // Reset the stream object so it can be used again.
    stream.Reset();

    // Start a background task that will decrypt a stream.
    task = crypt.DecryptStreamAsync(stream);
    success = task.Run();

    var n = eStrings.Count;
    for (i = 0; i <= n - 1; i++) {
        success = stream.WriteBytesENC(eStrings.GetString(i),"hex");
        if (stream.DataAvailable == true) {
            plainText = stream.ReadString();
            console.log(plainText);
        }

    }

    // Tell the background task that the stream has ended.
    success = stream.WriteClose();

    // Let's make sure the background task finished.
    // It should already be the case that the task is finished.
    while ((task.Finished !== true)) {
        task.SleepMs(20);
    }

    // Get any remaining data available from the stream.
    if (stream.DataAvailable == true) {
        plainText = stream.ReadString();
        console.log(plainText);
    }

    if (task.TaskSuccess !== true) {
        console.log("async decryption failed:");
        console.log(task.ResultErrorText);
        success = false;
    }

    console.log("-- decrypt finished --");

}

chilkatExample();