Ascon JS

TypeScript implementation of Ascon v1.2, an authenticated cipher and hash function http://ascon.iaik.tugraz.at/.

This implementation is a port of the Python version.

Usage

This library can be used both in the browser and in NodeJS.

Import the Ascon library as follows:

import { Ascon, randomBytes } from "ascon-js";

Hash

const message = new TextEncoder().encode("ascon");

const hash = Ascon.hash(message); // 32 byte hash

All four algorithms can be used. Fixed hash length of 32 bytes:

• Ascon-Hash (default)
• Ascon-Hasha

Variable hash length (should be >= 32 bytes):

• Ascon-Xof
• Ascon-Xofa

Ascon.hash(message, {
  variant: "Ascon-Xof",
  length: 64,
});

Encryption

// Generate a random key and a random nonce. This can be done using the helper method randomBytes
const key = randomBytes(16); // 16 bytes
const nonce = randomBytes(16); // 16 bytes

const plaintext = new TextEncoder().encode("ascon");

// Encrypt the plaintext using the key and the nonce
const ciphertext = Ascon.encrypt(key, nonce, plaintext);

Associated data

In addition to the plain text, associated data can be provided, which is used for additional data integrity checking.

Ascon.encrypt(key, nonce, plaintext, {
  associatedData: new TextEncoder().encode("additional data"),
});

Algorithms

All specified algorithms of Ascon encryption are implemented:

• Ascon-128 (default)
• Ascon-128a
• Ascon-80pq

The used algorithm can be specified using the options parameter.

const key = randomBytes(20); // 20 bytes

Ascon.encrypt(key, nonce, plaintext, {
  variant: "Ascon-80pq",
});

Decryption

const key = ...; // 16 bytes
const nonce = ...; // 16 bytes

const ciphertext = ...; // Encrypted data

// Decrypt the ciphertext using the key and the nonce
const plaintextResult = Ascon.decrypt(key, nonce, ciphertext);

const text = new TextDecoder().decode(plaintextResult); // "ascon"