@cbortech/hash-extension

Cryptographic hash application-string extension for @cbortech/cbor.

@cbortech/cbor is a TypeScript library for converting between CBOR, CDN, and JavaScript values.

A playground for @cbortech/cbor is published at https://cbor.tech/cbor/.

This extension implements the hash application-extension identifier from CDN. It computes a cryptographic hash and returns the output as a CBOR byte string.

Installation

npm install @cbortech/cbor @cbortech/hash-extension

Usage

import { CBOR } from '@cbortech/cbor';
import { hash } from '@cbortech/hash-extension';

const cbor = new CBOR({ extensions: [hash] });

// Parse CDN containing hash values.
const document = cbor.parse(`{
  "hash": hash'foo'
}`);
// document.hash is a bare Uint8Array.

// Convert CDN containing a hash value into CBOR.
const encoded = cbor.fromCDN("hash'foo'").toCBOR();
// encoded is CBOR binary data stored as a Uint8Array.
// Inspect the encoded CBOR value with toHexDump():
console.log(CBOR.fromCBOR(encoded).toHexDump());
// 58 20 2C 26 B4 6B 68 FF C6 8F F9 9B 45 3C 1D 30 41 34 13 42 2D 70 64 83 BF A0 F9 8A 5E 88 62 66 E7 AE  -- h'2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae'

// Format CDN with hash values as h'...'.
console.log(cbor.format(`{ "hash" : hash'foo' }`, { appStrings: false }));
// {"hash":h'2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae'}

CDN Forms

• hash'foo' computes SHA-256 over the UTF-8 text foo.
• hash<<'foo'>> computes SHA-256 over the byte string foo.
• hash<<"foo">> computes SHA-256 over the UTF-8 text foo.
• hash<<h'0102', -16>> computes SHA-256 over raw bytes.
• hash<<'foo', -44>> selects an algorithm by COSE integer ID.
• hash<<'foo', "SHA-512">> selects an algorithm by COSE algorithm name.

No uppercase HASH variant is defined.

Supported Algorithms

• -14 / SHA-1
• -15 / SHA-256/64
• -16 / SHA-256
• -17 / SHA-512/256
• -18 / SHAKE128
• -43 / SHA-384
• -44 / SHA-512
• -45 / SHAKE256

License

Apache-2.0