(Node.js) Streaming Encryption by Encrypting in Chunks

Encrypt data in chunks.

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() {

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    var crypt = new chilkat.Crypt2();

    crypt.CryptAlgorithm = "aes";
    crypt.CipherMode = "cbc";
    crypt.KeyLength = 128;

    crypt.SetEncodedKey("000102030405060708090A0B0C0D0E0F","hex");
    crypt.SetEncodedIV("000102030405060708090A0B0C0D0E0F","hex");

    crypt.EncodingMode = "hex";
    var txt1 = "The quick brown fox jumped over the lazy dog.\r\n";
    var txt2 = "-\r\n";
    var txt3 = "Done.\r\n";

    var sbEncrypted = new chilkat.StringBuilder();

    // Encrypt the 1st chunk:
    // (don't worry about feeding the data to the encryptor in 
    // exact multiples of the encryption algorithm's block size.
    // Chilkat will buffer the data.)
    crypt.FirstChunk = true;
    crypt.LastChunk = false;
    sbEncrypted.Append(crypt.EncryptStringENC(txt1));

    // Encrypt the 2nd chunk
    crypt.FirstChunk = false;
    crypt.LastChunk = false;
    sbEncrypted.Append(crypt.EncryptStringENC(txt2));

    // Now encrypt N more chunks...
    // Remember -- we're doing this in CBC mode, so each call
    // to the encrypt method depends on the state from previous
    // calls...
    crypt.FirstChunk = false;
    crypt.LastChunk = false;
    var i;
    for (i = 0; i <= 4; i++) {
        sbEncrypted.Append(crypt.EncryptStringENC(txt1));
        sbEncrypted.Append(crypt.EncryptStringENC(txt2));
    }

    // Now encrypt the last chunk:
    crypt.FirstChunk = false;
    crypt.LastChunk = true;
    sbEncrypted.Append(crypt.EncryptStringENC(txt3));

    console.log(sbEncrypted.GetAsString());

    // Now decrypt in one call.
    // (The data we're decrypting is both the first AND last chunk.)  
    crypt.FirstChunk = true;
    crypt.LastChunk = true;
    var decryptedText = crypt.DecryptStringENC(sbEncrypted.GetAsString());

    console.log(decryptedText);

    // Note: You may decrypt in N chunks by setting the FirstChunk
    // and LastChunk properties prior to calling the Decrypt* methods

}

chilkatExample();