evilcrypt


EvilCrypt is a collection of symmetric encryption algorithms that extend AES. Each algorithm version offers different parameters, such as key length, checksum length, or encryption speed, to suit various use cases.

Getting started

You can install the package using your preferred package manager:

``bash
bun install evilcrypt


or

pnpm install evilcrypt

or

npm install evilcrypt
`

To encrypt and decrypt a string, follow this example:

`javascript
import { randomBytes } from 'node:crypto';
import {
encrypt,
decrypt,
} from 'evilcrypt';

const message = 'Hello world!';
const message_buffer = Buffer.from(message, 'utf8');

const key = randomBytes(64);

const message_encrypted = await encrypt(message_buffer, key);
console.log(message_encrypted);
// Buffer(65) [Uint8Array] [
// 1, 234, 250, 99, 214, 36, 216, 43, 65, 68, 85,
// 20, 8, 3, 152, 234, 206, 228, 14, 184, 101, 62,
// 132, 217, 56, 131, 167, 87, 112, 128, 87, 242, 39,
// 249, 12, 190, 100, 87, 91, 145, 49, 112, 51, 96,
// 7, 23, 181, 182, 210, 171, 244, 220, 98, 163, 207,
// 86, 78, 139, 26, 176, 238, 48, 44, 77, 20
// ]

const message_decrypted = await decrypt(message_encrypted, key);
console.log(message_decrypted.toString('utf8'));
// 'Hello world!'
`

By default, the encrypt method uses algorithm v1. If you want to use a different algorithm, call the encrypt method of that specific version:

`javascript
import { v2 as evilcrypt_v2 } from 'evilcrypt';

const message_encrypted = await evilcrypt_v2.encrypt(message_buffer, key);
`

For decryption, use the decrypt method from the core module. It automatically detects the algorithm used to encrypt the message.

`javascript
import { decrypt } from 'evilcrypt';

const message = await decrypt(message_encrypted, key);
`

Algorithms

$3

| Parameter | Value |
| ------------------ | ------------- |
| AES algorithm | AES-256-CBC |
| PBKDF2 algorithm | PBKDF2-SHA256 |
| PBKDF2 iterations | 100 000 |
| Message padding length | 8...255 bytes |
| Checksum algorithm | SHA256 |
| Checksum length | 32 bytes |
| Key length | 64 bytes |

v1 is inspired by Telegram’s MTProto encryption. Its output is relatively long because it includes a 32-byte checksum and extensive padding. This makes it less suitable for encrypting short messages.

$3

| Parameter | Value |
| -------------------------- | -------------------- |
| AES algorithm | AES-256-CBC |
| PBKDF2 algorithm | PBKDF2-SHA256 |
| PBKDF2 iterations | 100 000 |
| Message padding length | 6 bits + 4...7 bytes |
| Checksum algorithm | PBKDF2-SHA256 |
| Checksum PBKDF2 iterations | 100 000 |
| Checksum length | 12 bytes |
| Key length | 64 bytes |

v2 is optimized for encrypting short messages, such as tokens. It produces shorter outputs compared to v1` due to its reduced checksum length. However, the checksum is computed using PBKDF2 with 100 000 iterations, making brute-force attempts more difficult. The padding length is also minimized, with a maximum length of 62 bits.