twilio/twilio-java — pull request #158 by jtamplin (2014-10-14 00:23:03+00:00)
Title: Fix a timing attack

The HMAC validation code early-exits on mismatch, which would allow an attacker to reconstruct the hash one byte at a time. Granted, assuming this is over SSL and SHA1 hasn't been broken there are still a number of obstacles that must be overcome, but better safe than sorry.