https://pip.pypa.io/en/stable/news/
https://github.com/pypa/pip/compare/8.0.2...8.1.0

Archive verified via:
https://pypi.python.org/packages/source/p/pip/pip-8.1.0.tar.gz.asc

And Donald's key from:
https://pypi.python.org/security

$ gpg --verify pip-8.1.0.tar.gz.asc pip-8.1.0.tar.gz
gpg: Signature made Sat, Mar  5, 2016  4:57:30 PM GMT using RSA key ID 3372DCFA
gpg: Good signature from "Donald Stufft (dstufft) <donald@stufft.io>"
gpg:                 aka "Donald Stufft (dstufft) <donald@python.org>"
...
Primary key fingerprint: 7C6B 7C5D 5E2B 6356 A926  F04F 6E3C BCE9 3372 DCFA