Twofish - Hardware Tradeoffs
(1) A "byte serial" implementation. It uses one clock per S-box lookup, and four clocks per h function (including the MDS). We allow two clocks for the PHT and key addition. With four h functions per round, each round requires 18 clock cycles.
(2) Uses a fully wired h function, but still computes the round keys on the fly. The other versions all precompute the round subkeys.
(3) A version that precomputes the S-boxes into dedicated RAM instead of computing the S-boxes on the fly.
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