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I need to
As I've only made auth with JWT so far, I'm not sure. If I use RSA, I guess I have to put the encrypted text in the body.
Do you think it can be used? Any other suggestions?
Is there a particular reason you want to use your own implementation instead of JWT? If you just want an alternative to JWT, there is also PASETO.
I wanted to let my users encrypt their payload with my public key so only I can decrypt that payload. Just like how PGP works. Eventually I've used hybrid encryption with AES for encrypting the payload and RSA for encrypting AES secret key.
Just to let you know this post is almost 2 years old :)
Idk why the other person said to not use RSA because of PKCS#1 padding vulns since 2048 RSA-OAEP should be fine for your use case. Just make sure to rotate keys and encrypt first with AES or some other symmetric encryption than RSA. Also, double check the libraries you're using and try to implent boring encryption which will reduce the probability of a misconfigured encryption algorithm. Also, make sure to secure the private key which can be done a number of ways.
I personally wouldn't use RSA for this, but that's just me.
I don't want to use RSA too but nothing better comes to my mind :)
This might help: https://www.scottbrady91.com/jose/json-web-encryption
Looks like it uses RSA so what I said above I think still applies.
EDIT: It is called JWE or JSON Web Encryption for help with what keywords you should search. There are also other symmetric algos you can use with RSA like chacha20, but I think it is best to start with AES just because it has been used for years and is very well documented.
TIL that RSA allows maximum 245 character payload. But I guess that doesn't apply to JWE. Thanks for the suggestion, I'm researching 🙏🫡
Sounds like you’re proposing WebAuthn which already exists. Keep in mind that there are attacks against RSA with PKCS1 padding. I’d use a more secure cryptographic primitive than RSA (I.e. elliptic curves) - there’s a reason cryptographic experts don’t look towards RSA these days.
If you're already using JWTs for the auth it seems like JWE.
However unless you're storing your tokens and payloads (like in a job queue) that might be overkill. If your standard REST/Graphql api is backed by SSL/TLS you get encryption in transit for free.