On 6/22/07, W Karas <[EMAIL PROTECTED]> wrote: > > > > Bin Chen wrote: > > Hi, > > > > Many cryptography algorithm used prime to do the modular math, but I > > don't know why it need to use prime but not many ordinary numbers? > > > > Thanks > > Bin > > I would guess it is because the integers modulo any prime are a > "field", whereas the integers modulo a non-prime are mearly a > "ring". More concretely, for any integer i and any prime p, there > is guaranteed to be an integer j such that i * j == 1 mod p. This > is not guaranteed when the modulus is not a prime.
And that is the trick used in RSA algorithm of cryptography. > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to algogeeks@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/algogeeks -~----------~----~----~----~------~----~------~--~---
