Review appreciated: Golang Crypto/Cert system

Hi all, This is intended for use in a larger project but I felt the need to abstract and containerise some of the crypto. It uses ECDSA and NaCl as provided in the Golang libraries, and I've tried to join them in as sensible a way as possible without making too many assumptions. Would appreciate some review to make sure I'm not screwing anything up: https://github.com/cathalgarvey/easykeys Thanks, Cathal