What are authorization tokens, and what types are there?

Authorization tokens are digital markers that confirm a user's or client's rights to access resources. They allow the server not to store session state but to verify rights via the token.

Main types of tokens:

• JWT (JSON Web Token) — a self-contained token with encrypted or signed information about the user and rights. Often used in REST API.
• OAuth tokens — used in the OAuth 2.0 protocol, include access tokens (for access) and refresh tokens (for renewing access tokens).
• Session tokens — session identifiers stored on the server in memory or database, and passed by the client in cookies.

Example of using JWT in Go:

import (
    "github.com/dgrijalva/jwt-go"
    "time"
)

func GenerateJWT(secret []byte) (string, error) {
    claims := jwt.StandardClaims{
        ExpiresAt: time.Now().Add(time.Hour).Unix(),
        Issuer:    "myapp",
    }
    token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
    return token.SignedString(secret)
}