conformal/btcec — pull request #5 by yrashk (2014-07-31 12:22:04+00:00)
Title: Signature's S, when over half order, has to be encoded differently

Reference implementation: https://github.com/bitcoin/bitcoin/blob/b7bba43a14a641b6b64bbf48357b2987c1b05800/src/key.cpp#L235-L238

ht @oleganza

Thoughts?