Two optimizations for verifySchnorr:
1. Jacobian x-coordinate check before toAffine:
Instead of converting to affine first (1 inversion = ~270 field ops),
check X == r·Z² in Jacobian coordinates (1 sqr + 1 mul = 2 ops).
Invalid signatures (x mismatch) are rejected immediately without
paying the inversion cost. Valid signatures still need inversion for
the y-parity check. For Nostr, ~all sigs are valid so this mainly
helps adversarial/spam rejection.
2. Inline wNAF zero-checks in mulDoubleG inner loop:
~70% of wNAF digits are zero. Previously, each still called
addWnafMixedPP (function call overhead: null checks, frame setup).
Now the zero-check is inlined before the call, avoiding ~364
function calls per verify. On ART (5-8ns per call), this saves
~2-3μs. On HotSpot, the JIT already optimized this — no change.
https://claude.ai/code/session_01EMY5RnXb9rnsyU2KbXrSaY
Claude
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