Among the many reactions to Neil Koblitz’ article on modern cryptography in the Notices of the AMS the most interesting reply I’ve read is this one by Steven Bellovin:
Mathematicians have known since Euclid that axioms are important. Security, though, is math embedded in the real world, and that matters. Put another way, Euclidean geometry is completely valid as a pure mathematical system. But that doesn’t mean it applies in a relativistic universe. Sure, we live far from any space-warping masses, so we can pretend that the angles in our triangles add up to 180 degrees. In the security world, though, the attacker will toss a black hole at us to warp the space around our provably-secure triangular encryptor. Was that proof of security flawed? Ask Riemann or Lobachevsky.