MWCryptHash.php

Go to the documentation of this file.

<?php
class MWCryptHash {
    protected static ?string $algo = null;
 
    protected static int $hashLength;
 
    public static function hashAlgo() {
        $algorithm = self::$algo;
        if ( $algorithm !== null ) {
            return $algorithm;
        }
 
        $algos = hash_hmac_algos();
        $preference = [ 'whirlpool', 'sha256' ];
 
        foreach ( $preference as $algorithm ) {
            if ( in_array( $algorithm, $algos, true ) ) {
                self::$algo = $algorithm;
                return $algorithm;
            }
        }
 
        throw new DomainException( 'Could not find an acceptable hashing function.' );
    }
 
    public static function hashLength( $raw = true ) {
        self::$hashLength ??= strlen( self::hash( '', true ) );
        // Optimisation: Skip computing the length of non-raw hashes.
        // The algos in hashAlgo() all produce a digest that is a multiple
        // of 8 bits, where hex is always twice the length of binary byte length.
        return $raw ? self::$hashLength : self::$hashLength * 2;
    }
 
    public static function hash( $data, $raw = true ) {
        return hash( self::hashAlgo(), $data, $raw );
    }
 
    public static function hmac( $data, $key, $raw = true ) {
        if ( !is_string( $key ) ) {
            // hash_hmac tolerates non-string (would return null with warning)
            throw new InvalidArgumentException( 'Invalid key type: ' . gettype( $key ) );
        }
        return hash_hmac( self::hashAlgo(), $data, $key, $raw );
    }
 
}