nodejs crypto - simple encrypt & decrypt using IV (Initialization Vector)

simple-nodejs-iv-encrypt-decrypt.js

"use strict";
var crypto = require("crypto");

var EncryptionHelper = (function () {

    function getKeyAndIV(key, callback) {

        crypto.pseudoRandomBytes(16, function (err, ivBuffer) {
    
            var keyBuffer  = (key instanceof Buffer) ? key : new Buffer(key) ;
            
            callback({
                iv: ivBuffer,
                key: keyBuffer
            });
        });
    }

    function encryptText(cipher_alg, key, iv, text, encoding) {

        var cipher = crypto.createCipheriv(cipher_alg, key, iv);

        encoding = encoding || "binary";

        var result = cipher.update(text, "utf8", encoding);
        result += cipher.final(encoding);

        return result;
    }

    function decryptText(cipher_alg, key, iv, text, encoding) {

        var decipher = crypto.createDecipheriv(cipher_alg, key, iv);

        encoding = encoding || "binary";

        var result = decipher.update(text, encoding);
        result += decipher.final();

        return result;
    }

    return {
        CIPHERS: {
          "AES_128": "aes128",          //requires 16 byte key
          "AES_128_CBC": "aes-128-cbc", //requires 16 byte key
          "AES_192": "aes192",          //requires 24 byte key
          "AES_256": "aes256"           //requires 32 byte key
        },
        getKeyAndIV: getKeyAndIV,
        encryptText: encryptText,
        decryptText: decryptText
    };
})();

module.exports = EncryptionHelper;

test.js

var encryptionHelper = require("./simple-nodejs-iv-encrypt-decrypt.js")
var story = "this is the story of the brave prince who went off to fight the horrible dragon... he set out on his quest one sunny day";
var algorithm = encryptionHelper.CIPHERS.AES_256;

console.log("testing encryption and decryption");
console.log("text is: " + story);

encryptionHelper.getKeyAndIV("1234567890abcdefghijklmnopqrstuv", function (data) { //using 32 byte key

    console.log("got key and iv buffers");

    var encText = encryptionHelper.encryptText(algorithm, data.key, data.iv, story, "base64");

    console.log("encrypted text = " + encText);

    var decText = encryptionHelper.decryptText(algorithm, data.key, data.iv, encText, "base64");

    console.log("decrypted text = " + decText);

    assert.equal(decText, story);
});

How can I run this encryption on Files instead of text ? Thanks...

@makmayank Read the file, encrypt the content, write encrypted content to the file.

missing var assert = require('assert'); in test.js?

Can you use Buffer.from(key) instead, due to its deprecation?

Yes if you have following message : DeprecationWarning: Buffer() is deprecated due to security and usability issues. Please use the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.

You can use Buffer.from(key) instead new Buffer(key)
But it's working only for variable contenting a string

For variable contenting a number you can change : new Buffer(num) to Buffer.alloc(num)

//CryptoJS example

var key = "H98zM6i/55yNJfkFsbu0HrzlFo17FtR9";
var iv = key.slice(0, 16);
//Create Key
key = CryptoJS.enc.Utf8.parse(key);
//Get Iv
iv = CryptoJS.enc.Utf8.parse(iv);
var encrypted = CryptoJS.AES.encrypt("testtest", key,{ iv: iv});
//Encrypt string
var encrypted_data = encrypted.toString();

console.log(encrypted_data)

var decrypted = CryptoJS.AES.decrypt(encrypted_data, key,{ iv: iv});
var decrypted_data = decrypted.toString(CryptoJS.enc.Utf8)

console.log(decrypted_data)