ParagonIE_Sodium_Core_Util::andStrings( string $a, string $b ): string

44    public static function andStrings($a, $b)45    {46        /* Type checks: */47        if (!is_string($a)) {48            throw new TypeError('Argument 1 must be a string');49        }50        if (!is_string($b)) {51            throw new TypeError('Argument 2 must be a string');52        }53        $len = self::strlen($a);54        if (self::strlen($b) !== $len) {55            throw new SodiumException('Both strings must be of equal length to combine with bitwise AND');56        }57        return $a & $b;58    }