> OpenSSL outperforms libtomcrypt by a significant factor (easily 2x) in most cases.

Gregory, do you have any evidence to substantiate this claim? Not that it isn't plausible, but I couldn't find any benchmarks, and here the author of libtomcrypt finds it to be 40% faster than OpenSSL concerning RSA operations.

http://www.adras.com/TomsFastMath-faster.t71-93.html

>  but I am generally in favor of absolute performance per byte of all algorithms concerned being available

Performance isn't all that matters, or else Python would have used GMP, as Guido discussed here:

http://mail.python.org/pipermail/python-3000/2007-September/010329.html

It is also not a convincing argument that new python libraries should use OpenSSL if possible just because that is what _ssl uses. Compiling Python with OpenSSL support has been optional because it puts additional restrictions on the PSF license. Spreading this restriction to the future crypto module (when we have a choice not to) doesn't make sense.