libsodium18 1.0.13-1 (s390x binary) in ubuntu artful

 NaCl (pronounced "salt") is a new easy-to-use high-speed software library for
 network communication, encryption, decryption, signatures, etc.
 .
 NaCl's goal is to provide all of the core operations needed to build
 higher-level cryptographic tools.
 .
 Sodium is a portable, cross-compilable, installable, packageable fork of NaCl,
 with a compatible API.