Why we need to use modular arithmetic in cryptography like Diffie hellman and RSA problm?
there's a decent explanation of Diffie Hellman on wikipedia, too, if you want some more information on what exactly is going on.
Thanks friend. So as my Professorr said mod provide the security of crypto systems. I saw in some books that because mod arithmetic is easy to with in computers, and to avoid integer division errors people use it. But it seems more than that since it provide one way function so that it is use. Thanky you once again