src/Util.php
public function hashPersonalMessage(string $message)
    {
        $prefix = sprintf("\x19Ethereum Signed Message:\n%d", mb_strlen($message));
        return $this->sha3($prefix . $message);
    }
public function hashPersonalMessage(string $message)
    {
        $prefix = sprintf("\x19Ethereum Signed Message:\n%d", mb_strlen($message));
        return $this->sha3($prefix . $message);
    }
hasPersonalMessage

@param string $message
@return string