libsecp256k1-0 0.1~20170810-2 (arm64 binary) in ubuntu cosmic

 An optimized C library for EC operations on curve secp256k1.
 .
 NB! This library is a work in progress and is being used to research
 best practices. Use at your own risk.
 .
 Features:
  * secp256k1 ECDSA signing/verification and key generation.
  * Adding/multiplying private/public keys.
  * Serialization/parsing of private keys, public keys, signatures.
  * Constant time, constant memory access signing and pubkey generation.
  * Derandomized DSA (via RFC6979 or with a caller provided function.)
  * Very efficient implementation.