I just learned how to lookup a user's info on pgp.mit.edu. Is there some way to determine what algorithm the user is using?
migrated from crypto.stackexchange.com Jan 30 '14 at 19:29This question came from our site for software developers, mathematicians and others interested in cryptography. 


That's basically right. The details of what algorithm his keypair is for is actually encoded as part of the publickey itself! That is the publickey is not really a raw key but instead it is packaged a bit to specify some details of the key (minimally the algorithm the key is for) as well as the key bitstring itself. You can find more by reading about RSA PKCS#1 [published by IETF as RFC3447]: http://tools.ietf.org/html/rfc3447#section3.1 

