What is a JWT?
A JWT consists of three parts: a Header, a Payload, and a Signature. They are separated by dots and Base64URL encoded.
Common JWT Security Pitfalls
- 'None' Algorithm Attack: An attacker might change the signing algorithm to "none" to bypass verification.
- Weak Secret Keys: Using a simple symmetric key like '123456' allows hackers to forge tokens in seconds.
- Sensitive Data Exposure: Remember that the Payload is encoded, NOT encrypted. Never store passwords in it.
How to Debug JWTs Safely?
Developers often need to inspect Token contents. When using online debuggers, ensure the platform doesn't store your tokens on their servers. The JWT debugger at tool.tl runs entirely in your browser, keeping your authentication data private.
Best Practices
Always use strong signing algorithms (like HS256 or RS256) and rotate your secrets regularly. In production, always use HTTPS to prevent Token interception during transit.