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Cryptography

Libauth includes a variety of fast, efficient, WebAssembly-based cryptographic primitives:

Several higher-level utilities are also composed from these primitives:

Hashing Primitives

The ripemd160, sha1, sha256, and sha512 utilities each share an identical interface. For each, Libauth exports an internal instance of the relevant WebAssembly implementation which can be used immediately after import, e.g. to sha256 hash a utf8-encoded message:

import { binToHex, sha256, utf8ToBin } from '@bitauth/libauth';

const message = utf8ToBin('Hello world!');
const hash = sha256.hash(message);
const hex = binToHex(hash);
console.log(hex);
// => 'c0535e4be2b79ffd93291305436bf889314e4a3faec05ecffcbb7df31ad9e51a'

To ripemd160 hash a message from a hex-encoded string:

import { binToHex, hexToBin, ripemd160 } from '@bitauth/libauth';

const message = hexToBin('01020304');
const hash = ripemd160.hash(message);
const hex = binToHex(hash);
console.log(hex);
// => '179bb366e5e224b8bf4ce302cefc5744961839c5'

Note that each hashing primitive also supports an incremental/stream hashing API:

import { binToHex, ripemd160 } from '@bitauth/libauth';
const step1 = ripemd160.update(ripemd160.init(), Uint8Array.of(0x01));
const step2 = ripemd160.update(step1, Uint8Array.of(0x02));
const step3 = ripemd160.update(step2, Uint8Array.of(0x03));
const step4 = ripemd160.update(step3, Uint8Array.of(0x04));
const hash = ripemd160.final(step4);
const hex = binToHex(hash);
console.log(hex);
// => '179bb366e5e224b8bf4ce302cefc5744961839c5'

Secp256k1

Like the hashing primitives, Libauth exports an internal instance of the Secp256k1 WebAssembly implementation which can be used immediately after import, e.g.:

import { secp256k1 } from '@bitauth/libauth';
import { msgHash, pubkey, sig } from 'somewhere';

secp256k1.verifySignatureDERLowS(sig, pubkey, msgHash)
  ? console.log('🚀 Signature valid')
  : console.log('❌ Signature invalid');

Tip

Libauth offers a wide variety of higher-level utilities which make use of secp256k1; few applications need to use secp256k1 directly. See, for example, Verifying Transactions or Wallets & Transaction Creation.

The secp256k1 object includes the following methods:

  • addTweakPrivateKey
  • addTweakPublicKeyCompressed
  • addTweakPublicKeyUncompressed
  • compressPublicKey
  • derivePublicKeyCompressed
  • derivePublicKeyUncompressed
  • malleateSignatureCompact
  • malleateSignatureDER
  • mulTweakPrivateKey
  • mulTweakPublicKeyCompressed
  • mulTweakPublicKeyUncompressed
  • normalizeSignatureCompact
  • normalizeSignatureDER
  • recoverPublicKeyCompressed
  • recoverPublicKeyUncompressed
  • signMessageHashCompact
  • signMessageHashDER
  • signMessageHashRecoverableCompact
  • signMessageHashSchnorr
  • signatureCompactToDER
  • signatureDERToCompact
  • uncompressPublicKey
  • validatePrivateKey
  • validatePublicKey
  • verifySignatureCompact
  • verifySignatureCompactLowS
  • verifySignatureDER
  • verifySignatureDERLowS
  • verifySignatureSchnorr

For details on each method, see Secp256k1 in the API reference.

Note that Libauth also includes a validateSecp256k1PrivateKey function which does not require the Secp256k1 WebAssembly implementation.