RbNaCl::Libsodium
RbNaCl is a Ruby wrapper for libsodium, a portable version of the Networking and Cryptography library (NaCl) created by Daniel J. Bernstein.
tl;dr: it's one of the best crypto libraries around.
rbnacl-libsodium packages the libsodium library as a Ruby Gem so you don't have to worry about installing it through system packages. It builds just like a native extension, but since RbNaCl is implemented with FFI, works on JRuby too!
Installation
Add this line to your application's Gemfile:
gem 'rbnacl-libsodium'
And then execute:
$ bundle
Or install it yourself as:
$ gem install rbnacl-libsodium
Usage
require 'rbnacl/libsodium'
will tweak search path allowing rbnacl
to find bundled libsodium