Node.js encrypts large file using AES

Question

I try to use following code to encrypt a file of 1 GB. But Node.js abort with "FATAL ERROR: JS Allocation failed - process out of memory". How can I deal with it?

var fs = require('fs');
var crypto = require('crypto');
var key = "14189dc35ae35e75ff31d7502e245cd9bc7803838fbfd5c773cdcd79b8a28bbd";
var cipher = crypto.createCipher('aes-256-cbc', key);
var file_cipher = "";
var f = fs.ReadStream("test.txt");
f.on('data', function(d) {
    file_cipher = file_cipher + cipher.update(d, 'utf8', 'hex');
});
f.on('end', function() {  
    file_cipher = file_cipher + cipher.final('hex');
});

mscdex · Accepted Answer · 2016-11-26T20:45:12.547

48

You could write the encrypted file back to disk instead of buffering the entire thing in memory:

var fs = require('fs');
var crypto = require('crypto');

var key = '14189dc35ae35e75ff31d7502e245cd9bc7803838fbfd5c773cdcd79b8a28bbd';
var cipher = crypto.createCipher('aes-256-cbc', key);
var input = fs.createReadStream('test.txt');
var output = fs.createWriteStream('test.txt.enc');

input.pipe(cipher).pipe(output);

output.on('finish', function() {
  console.log('Encrypted file written to disk!');
});

edited Nov 26 '16 at 20:45

answered Dec 07 '14 at 18:04

mscdex

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Thanks! BTW, how can I know when the encryption is done? – Jan Leo Dec 07 '14 at 18:12
5

You can listen for the [`finish`](http://nodejs.org/docs/latest/api/stream.html#stream_event_finish) event on `output`. – mscdex Dec 07 '14 at 18:18
How to decrypt the same file? – sarath Dec 26 '16 at 12:48
3

You can decrypt in the exact same way by using `crypto.createDecipher` instead of `crypto.createCipher`. – Ryan Plant Feb 28 '17 at 15:05
During decryption, how would I handle the wrong key? @RyanPlant – Rahul Dec 11 '17 at 18:58
This work great but when i minimize my window streaming is stoped – Manoj Bhardwaj Oct 18 '18 at 11:32
3

[createCipher is deprecated](https://nodejs.org/api/crypto.html#crypto_crypto_createcipher_algorithm_password_options) – SamB May 02 '20 at 06:12
For a similar program using up-to-date methods, see [this response](https://stackoverflow.com/a/60370205/11609642). – AirOne Feb 12 '22 at 16:38

Ihor Sakailiuk · Answer 2 · 2022-01-05T16:05:31.230

crypto.createCipher() without initialization vector is deprecated since NodeJS v10.0.0 use crypto.createCipheriv() instead.

You can also pipe streams using stream.pipeline() instead of pipe method and then promisify it (so the code will easily fit into promise-like and async/await flow).

const {createReadStream, createWriteStream} = require('fs');
const {pipeline} = require('stream');
const {randomBytes, createCipheriv} = require('crypto');
const {promisify} = require('util');

const key = randomBytes(32); // ... replace with your key
const iv = randomBytes(16); // ... replace with your initialization vector

promisify(pipeline)(
        createReadStream('./text.txt'),
        createCipheriv('aes-256-cbc', key, iv),
        createWriteStream('./text.txt.enc')
)
.then(() => {/* ... */})
.catch(err => {/* ... */});

With NodeJS 15+ you could simplify it (skip promisify part)

const {createReadStream, createWriteStream} = require('fs');
const {pipeline} = require('stream/promises');
const {randomBytes, createCipheriv} = require('crypto');

const key = randomBytes(32); // ... replace with your key
const iv = randomBytes(16); // ... replace with your initialization vector

pipeline(
  createReadStream('./text.txt'),
  createCipheriv('aes-256-cbc', key, iv),
  createWriteStream('./text.txt.enc')
)
.then(() => {/* ... */})
.catch(err => {/* ... */});

Me getting this error while decrypting the file `Error: Unsupported state or unable to authenticate data` — Prathamesh More, Jul 23 '20 at 14:05
@PrathameshMore It's difficult to say where the issue is without seeing the code for file decryption. Please note, you should store your key and initialization vector somewhere (e.g. file), `randomBytes` was used only for demonstration purpose. — Ihor Sakailiuk, Jul 24 '20 at 08:47
Stream Promises API is available since Node Version 15 ([docu](https://nodejs.org/docs/latest-v15.x/api/stream.html#stream_streams_promises_api)) — Felix Lechenbauer, Jan 05 '22 at 11:31

score 3 · Answer 3 · edited Mar 28 '23 at 09:07

3

I would simply use the Fileger to do it. It's a promise-based package and a clean alternative to the NodeJS filesystem.

const fileger = require("fileger")
const file = new fileger.File("./your-file-path.txt");

file.encrypt("your-password") // this will encrypt the file
   .then(() => {
      file.decrypt("your-password") // this will decrypt the file
   })

edited Mar 28 '23 at 09:07

Lee Goddard

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answered Apr 18 '20 at 11:23

Paul Hanneforth

53
2
7

Node.js encrypts large file using AES

3 Answers3

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