However , Szabo 's method of double-spending protection was vulnerable to Sybil attacks . Szabo 's method of double protection , however , was vulnerable to Sybil attacks .
Walau bagaimanapun, kaedah Szabo untuk perlindungan perbelanjaan berganda terdedah kepada serangan Sybil. Kaedah perlindungan berganda Szabo, bagaimanapun, terdedah kepada serangan Sybil.