Theorem: The rate of a reliable PRQS attack is tightly bounded above by protocol capacity

• A channel cannot transmit reliably at rates above capacity

• Corollary: The capacity of a protocol is the (tight) upper bound on the rate of a reliable DRQS attack.

• While the protocol is not perfect, there is a cost to exploiting its non-perfectness

• Bound also holds for: n → 0 ; adaptive, non-deterministic; also many other protocols

• i.e. n → 0  lim k/n  C

Notes: