someone did "SELFISH MINING (BLOCK WITHHOLDING ATTACK)" last night.
Many mined blocks was orphaned. Even with 5+ confirms.

https://bitcointalk.org/topic=392436.msg37365161#msg37365161

だそうだ
めちゃくちゃ前にこの攻撃ビットコインでもあったんじゃないっけか？
マイニング能力30%ぐらいで実質51%掌握出来ちゃうとかいうやつ
マイナー離れしないといいけどな