Tested with Cuis 4.2 revision 2972; libsodium 1.0.2 on Intel and ARM processors
Cuis interface to NaCl (pronounced "salt") cryptographic library
Ported to Cuis from the Squeak/Pharo code originally by Tony Garnock-Jones http://www.eighty-twenty.org/index.cgi/tech/smalltalk/nacl-for-squeak-and-pharo-20130601.html
Get and install the NaCl (salt) code https://github.com/jedisct1/libsodium
Load the package in Cuis 4.2
Feature require: 'Crypto-NaCl'. "Note NaCl has $N and $C capitalized"
Note simple end-to-end usage example: NaclTests>>TestExampleHighLevel
If zero unit tests pass, be sure to place the libsodium library file (libsodium.so on Linux) in your image directory (probably Cuis-Smalltalk-Dev).