JSON Web Tokens
A JSON Web Token, or JWT, is a JSON-based open standard for creating tokens that assert some number of claims. JWTs are frequently used as authentication tokens. In this context, the claims are typically statements about the identity and permissions of an authenticated user. The tokens are cryptographically signed, which makes it possible to verify that the content of the token has not been modified since it was issued. You can learn all about this technology on the website (https://jwt.io/).
This type of token is comprised of three sections, separated by a dot, in the format A.B.C. B is the payload, which is where we put the claims. C is the signature, which is used to verify the validity of the token, and A is a header, which identifies the token as a JWT, and indicates the algorithm used to compute the signature. A, B, and C are all encoded with a URL-safe Base64 encoding (which we'll refer to as Base64URL). The Base64URL encoding makes it possible to use...