bitcoin/secp256k1 — pull request #16 by peterdettman (2014-05-19 11:39:21+00:00)
Title: Implement batch inversion of field elements

Adds secp256k1_fe_inv_all and secp256k1_fe_inv_all_var methods for batch inversion of field elements, implemented using "Montgomery's Trick", which uses only one actual field inversion, trading off the others for 3 field multiplications each.

Includes randomised tests covering the new methods and also coverage for the existing inv/inv_var methods.