What protection does JWT use?
The signature can be generated by using both symmetric (HMAC algorithms) or asymmetric keys (RSA or ECDSA). Additionally JWT can carry encrypted data (JWE, RFC 7516) to protect sensitive data, although we won’t see it in this study.
What protection does a JSON Web Token JWT offer to mitigate tampering with its contents?
Here ciphering is added mainly to hide internal information but it’s very important to remember that the first protection against tampering of the JWT token is the signature. So, the token signature and its verification must be always in place.
Can someone steal a JWT?
Yes! If a JWT is stolen, then the thief can can keep using the JWT. An API that accepts JWTs does an independent verification without depending on the JWT source so the API server has no way of knowing if this was a stolen token! This is why JWTs have an expiry value.
What can a JWT do to protect against hijacking?
JWTs in themselves offer no protection against this. There are authentication schemes which provide protection even if the communication channel is compromised. These are called signature schemes. They work by signing the HTTP requests, hence the name. They are complicated, without a standard and used mostly between backend communications.
Is there a server component for JWT token?
There’s no server component, except for blacklisting that token, that can protect the user and the data stored. To sum up: JWT’s only real defense is expiry of the token.
How are JWTs used to share authentication information?
If you are using JWTs over an HTTP connection, there is not much you can do to prevent the attacker from sniffing your traffic and misusing the token. JWT are self sufficient tokens which are used to share authentication information between different systems.
What does it mean to have a JWT that does not expire?
I said until recently above, because with the advent of JWT, JSON Web Tokens, JWT usually acts as a stateless token. The server has no knowledge of that token other than what the token self-describes. This is also called an assertion. There are of course mitigations to keep people from asserting things such as signing the token.