libsodium is a portable repackaging of NaCl, a high-level crypto
library.
RbNaCl is the Ruby wrapper:
https://github.com/cryptosphere/rbnacl
rbnacl-libsodium is a gem which contains the complete libsodium sources
and
will compile them on installation much like other gems with native
dependencies.
However, unlike other gems with native dependencies, RbNaCl is written
with
FFI and rbnacl-libsodium will install on JRuby and other non-CRuby
Rubies!