As mentioned in README, nacl.util are included for convenience and were not build to be fast or compatible with many environments. People are encouraged to use external base64 and utf8 encoders. Since most of the issues in this tracker are related to those little utils — #44, #84 (even external "pen test" pointed out something about them — #38), we should just move them to separate package and keep TweetNaCl clean, and to really make people use something else.