SSH: TerrapinAttack
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Terrapin Attack: Breaking SSH Channel Integrity By Sequence Number Manipulation
mitm条件下，操纵handshake sequence计数，drop关键extinfo，实施downgrade attack。
symmetric cipher mode影响的分析比较漂亮, something synced is influnenced by seq number。
核心还是full transcript hash，参考sequence number reset, handshake与record互不影响；end-of-communication message，标识h结束。
