Two critical bugs fixed:
1. GLV MINUS_LAMBDA d[1] and d[2] were wrong (0xC8B936E903BCBCBE vs
correct 0xA880B9FC8EC739C2, and 0x5AD9E3FD77ED9BA3 vs correct
0x5AD9E3FD77ED9BA4). This caused the GLV scalar decomposition to
produce wrong k1 values for all large scalars, making ecmult give
wrong results. Verified by checking lambda^3 mod n == 1.
2. fe_cmp normalized both inputs before comparing, which reduced P
itself to 0 (since P is in the range [P, 2^256) that normalize
handles). This caused the "r < p" check in verify to fail for ALL
valid signatures. Fixed by comparing raw limb values.
Sign + verify + verify_fast now work correctly for small keys (1-3).
Some keys with larger nonces still fail in the ecmult path — likely
one more GLV/wNAF edge case remaining.
https://claude.ai/code/session_011KVZhDcV2G7idNWEBz12GY
Claude
fefbb243f0