php-keccak 
Pure PHP implementation of Keccak (SHA-3)
Usage
<?php
use kornrunner\Keccak;
Keccak::hash('', 224);
// f71837502ba8e10837bdd8d365adb85591895602fc552b48b7390abd
Keccak::hash('', 256);
// c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470
Keccak::hash('', 384);
// 2c23146a63a29acf99e73b88f8c24eaa7dc60aa771780ccc006afbfa8fe2479b2dd2b21362337441ac12b515911957ff
Keccak::hash('', 512);
// 0eab42de4c3ceb9235fc91acffe746b29c29a8c366b7c60e4e67c466f36a4304c00fa9caf9d87976ba469bcbe06713b435f091ef2769fb160cdab33d3670680e
Keccak::shake('', 128, 256);
// 7f9c2ba4e88f827d616045507605853ed73b8093f6efbc88eb1a6eacfa66ef26
Keccak::shake('', 256, 512);
// 46b9dd2b0ba88d13233b3feb743eeb243fcd52ea62b81b82b50c27646ed5762fd75dc4ddd8c0f200cb05019d67b592f6fc821c49479ab48640292eacb3b7c4be
0x9c7b7a00972121fb843af7af74526d7eb585b171