On Fri, 31 May 2002, surinder pal singh makkar wrote:
I am a newbie in cryptography. What I have learnt till now is that in assymeric cryptography scenario we have a private key and we generate the public key corresponding to it and then we send it to the central agency.
You don't have to send the public key to a repository, it's just convienient.
Suppose after sometime I have a private key and the public key. Is there some software tool which can tell me whether the public key is the same corresponding to the private key I am having. Also is there some tool which can tell me whether the keys have been curropted or not
With ECC you just recompute the public key from the private key and make sure it matches what's out in public. With RSA you just pick some random value (not zero or 1) and see if r^(e*d) = 1 mod N, or if you know p and q (where N = p*q) check that e*d = 1 mod (p-1)*(q-1). It's the same thing as encrypting/decrypting something to see if you get the same thing back. If not, something is wrong. I'm not sure how you can tell which key might be corrupted. For the public side, having the key reside in many places would do it - you can just check that they are all the same. so it may well be that saving the public key in a private place for that purpose is also useful. Patience, persistence, truth, Dr. mike