ruby-jwt 1.5.6-1 (amd64 binary) in ubuntu bionic

 A JSON Web Token (JWT) is a compact token format intended for space
 constrained environments such as HTTP Authorization headers and URI query
 parameters, and used as a means of representing claims to be transferred
 between two parties. The claims in a JWT are encoded as a JSON object that is
 digitally signed.
 .
 The JWT specification supports several algorithms for cryptographic signing.
 This library currently supports HMAC (HS256, HS384, HS512) and RSA
 (RS256, RS256, RS512). Unsigned plaintext JWT's are supported too.