README

Pure-PHP Keccak-256, SHA-3 and SHAKE hashing — the keccak256 primitive behind Ethereum addresses, ABI selectors and EVM signatures.

amashukov/keccak-php is a pure-PHP implementation of the Keccak / SHA-3 family of cryptographic hash functions, including the SHAKE extendable-output functions (XOF). It provides the keccak256 hash primitive used across Ethereum and other modern blockchains for address derivation, ABI function selectors and EIP-191 / EIP-712 message signing. Zero composer dependencies — only ext-mbstring from PHP core.

Features

• Keccak-256 — the exact hash Ethereum uses for keccak256, address derivation and ABI selectors.
• Full SHA-3 family — output sizes 224, 256, 384, 512.
• SHAKE128 / SHAKE256 extendable-output functions with arbitrary output length.
• Hex or raw binary output via a single raw_output flag.
• Pure PHP — no native extension to compile, no FFI; runs anywhere PHP 8.3 runs.
• Zero composer dependencies — ext-mbstring only.
• PHPStan level 9 clean, @PER-CS formatted, CI-tested.

Installation

composer require amashukov/keccak-php

Usage

use Amashukov\Keccak\Keccak;

// Hex-encoded hash output (default).
$digest = Keccak::hash('hello world', 256);
// → 47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad

// Raw 32-byte binary output.
$raw = Keccak::hash('hello world', 256, raw_output: true);

Supported output sizes: 224, 256, 384, 512. SHAKE variants:

$xof = Keccak::shake('hello world', security_level: 128, outlen: 256);

Requirements

• PHP 8.3+
• ext-mbstring

No composer dependencies.

Related packages

Part of a modular pure-PHP blockchain toolkit:

Quality

• PHPStan level 9.
• php-cs-fixer with the @PER-CS ruleset.
• GitHub Actions CI on every push.
• Test vectors validated against the published Keccak / SHA-3 reference outputs.

License

MIT License.