MWCryptHash.php

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<?php
class MWCryptHash {
    protected static $algo = null;
 
    protected static $hashLength = [
        true => null,
        false => null,
    ];
 
    public static function hashAlgo() {
        if ( !is_null( self::$algo ) ) {
            return self::$algo;
        }
 
        $algos = hash_algos();
        $preference = [ 'whirlpool', 'sha256', 'sha1', 'md5' ];
 
        foreach ( $preference as $algorithm ) {
            if ( in_array( $algorithm, $algos ) ) {
                self::$algo = $algorithm;
 
                return self::$algo;
            }
        }
 
        // We only reach here if no acceptable hash is found in the list, this should
        // be a technical impossibility since most of php's hash list is fixed and
        // some of the ones we list are available as their own native functions
        // But since we already require at least 5.2 and hash() was default in
        // 5.1.2 we don't bother falling back to methods like sha1 and md5.
        throw new DomainException( "Could not find an acceptable hashing function in hash_algos()" );
    }
 
    public static function hashLength( $raw = true ) {
        $raw = (bool)$raw;
        if ( is_null( self::$hashLength[$raw] ) ) {
            self::$hashLength[$raw] = strlen( self::hash( '', $raw ) );
        }
 
        return self::$hashLength[$raw];
    }
 
    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 ) ) {
            // a fatal error in HHVM; an exception will at least give us a stack trace
            throw new InvalidArgumentException( 'Invalid key type: ' . gettype( $key ) );
        }
        return hash_hmac( self::hashAlgo(), $data, $key, $raw );
    }
 
}