Secure JWT Implementation Best Practices
Store, rotate, and revoke JWTs safely in production applications.
Core Principle
JWTs are only as secure as their implementation. The spec is flexible; flexibility creates vulnerabilities. Follow these best practices to avoid the common pitfalls that have led to authentication bypasses in production systems.
Pin the Algorithm
Always specify the expected algorithm explicitly: jwt.decode(token, key, algorithms=["RS256"]). Never read the algorithm from the token header to select the verification key or code path. This prevents alg=none and key confusion attacks.
All lessons in this course
- JWT Anatomy: Header, Payload, Signature
- HS256 vs RS256: Symmetric vs Asymmetric JWTs
- JWT Vulnerabilities: alg=none & Key Confusion
- Secure JWT Implementation Best Practices