JWT best practices: A guide to secure authentication

JSON Web Tokens (JWTs) are widely used for representing claims between parties in distributed systems due to their compact and self-contained nature, but they come with potential pitfalls that can weaken authentication systems if misused. The guide emphasizes the importance of selecting the right algorithms, validating claims, handling expiration and revocation, and securely storing tokens on the client side. It advises against using the "none" algorithm, warns about algorithm confusion attacks, and stresses the necessity of distinguishing between signed and encrypted tokens. Key management is crucial, including the use of long, random keys stored in a secrets manager and regular key rotation. The guide also highlights the importance of short-lived access tokens, refresh token rotation, and avoiding storing sensitive data in JWT payloads. It warns against common mistakes like trusting the algorithm header, skipping audience validation, or treating JWT size casually. Ultimately, JWTs should be treated as verifiable claims with a short shelf life, with thorough validation and secure key management practices in place.