function getPublicKeyFingerprint($algorithm = 'md5')
    {
        if (empty($this->modulus) || empty($this->publicExponent)) {
            return false;
        }

        $modulus = $this->modulus->toBytes(true);
        $publicExponent = $this->publicExponent->toBytes(true);

        $RSAPublicKey = pack('Na*Na*Na*', strlen('ssh-rsa'), 'ssh-rsa', strlen($publicExponent), $publicExponent, strlen($modulus), $modulus);

        switch ($algorithm) {
            case 'sha256':
                $hash = new Hash('sha256');
                $base = base64_encode($hash->hash($RSAPublicKey));
                return substr($base, 0, strlen($base) - 1);
            case 'md5':
                return substr(chunk_split(md5($RSAPublicKey), 2, ':'), 0, -1);
            default:
                return false;
        }
    }