Python 2.5 includes a new module - hashlib - that supports hashes (SHA256 and possibly RIPEMD160) for which Portage would otherwise need the external pycrypto package. If pycrypto is unavailable, and hashlib exists and provides the required hashes, Portage should use it. (In particular, this would simplify upgrading to Python 2.5).
Created attachment 97653 [details, diff] Proposed patch to portage_checksum.py A patch to portage_checksum.py to use hashlib if it's available and pycrypto isn't.
It might be worth it to prefer hashlib over pycrypto. Some limited benchmarking indicates hashlib (using openssl) is faster than pycrypto is, and it is probably at least as reliable too (I only skimmed the patch, so if it already does that then please ignore me).
Created attachment 97838 [details, diff] New patch to portage_checksum.py Previous patch had a bug which caused it to fail if using pycrypto. (The patch still only uses hashlib as a fallback if pycrypto is unavailable - it should be fairly easy to modify it to use hashlib over pycrypto though, should it be worth doing so.)
This has been released in 2.1.3_rc6.