sec_karatsuba

[Torbjorn Granlund]

nisse at lysator.liu.se (Niels Möller) writes:

  I'd expect that the common case will be that it recurses to basecase
  only. The largest secret numbers in important cryptographic applications
  I'm aware of is about 2048 bits (32 limbs on a 64-bit machine), the
  secret factors for 4096-bit RSA.
  
We should not forget that code simplicity is more important for the sec
functions than for GMP in general.  The speedup we might see for the
2048-bit arithmetic of RSA-4096 is probably not very large, making the
code complexity tradeof suggest that Karatsuba is not an obvious
improvement.

If really large operands are needed for sec applications, than things
are different, of course.


Torbjörn