rubygems/rubygems — pull request #453 by pietro (2013-02-13 18:01:03+00:00)
Title: Add support to encrypt the private key used to sign gems.

I'm using 3DES to encrypt the key, but that can be easily changed/ made customizable by users.
I'm using ENV['GEM_PRIVATE_KEY_PASSPHRASE'] as the key passphrase because I couldn't find a way to ask the user when OptionParser is parsing the command line options or to automatically test when OpenSSL asks for it.