View Full Version : E changed to 1 in RSA algo.

November 7th, 2001, 02:24
I heard that DAMN changed e to 1 in ffxp to crack it, yes i know e is the public exponent but how it helps changing it to 1 ?


November 7th, 2001, 11:12
Hello Problem (we all have them, don't we?) !

Very easy!

M = C^E mod N (C = ciphertext, M = message)
C = M^D mod N (C = ciphertext, M = message)

We don't know D and it's very difficult to get D in reasonable time.
We know E.

So if we change E to 1, D must be 1 too and we have

M = C mod N
C = M mod N

and so we have C = M if M < N.