Does a rejection for public key needs to be based on its algorithm or its bits?

[martgil]

Hello @twiss,

Good afternoon OpenPGP.js team!

I am curious about how OpenPGP.js considers weak key types. I am a new learner here, so I apologize if this question is nonsensical or inappropriate.

I know that the team decided to reject ElGamal and DSA key types based on the following links here:

openpgpjs/src/config/config.js

Line 247 in 026b348

rejectPublicKeyAlgorithms: new Set([enums.publicKey.elgamal, enums.publicKey.dsa]),

openpgpjs/src/key/helper.js

Line 397 in 026b348

if (config.rejectPublicKeyAlgorithms.has(keyAlgo)) {

But I'd like to know when it will be considered a weak key. For example, would it still be correct to consider an ElGamal key weak if it is composed of 4096 bits?

Answers mean a lot to me. thank you in advance!

[larabr]

ElGamal and DSA have been deprecated by the crypto-refresh on security grounds (see https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-13.html#section-12.5 and https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-13.html#section-12.6), so it's not based on the key size for them 🙂

[martgil]

Very informative! Thank you very much, have a great day!