library for EC operations on curve secp256k1

 An optimized C library for EC operations on curve secp256k1.
 .
 NB! This library is intended to be
 the highest quality publicly available library
 for cryptography on the secp256k1 curve.
 However, the primary focus of its development has been
 for usage in the Bitcoin system
 and usage unlike Bitcoin's may be less well tested, verified,
 or suffer from a less well thought out interface.
 Correct usage requires some care and consideration
 that the library is fit for your application's purpose.
 .
 Features:
  * secp256k1 ECDSA signing/verification and key generation.
  * Additive and multiplicative tweaking of secret/public keys.
  * Serialization/parsing of secret keys, public keys, signatures.
  * Constant time, constant memory access signing and public key generation.
  * Derandomized ECDSA (via RFC6979 or with a caller provided function.)
  * Very efficient implementation.
  * Suitable for embedded systems.
  * Optional module for public key recovery.
  * Optional module for ECDH key exchange.