tldr: is there a way to upload package to hackage from Travis automatically and safely (hiding password to hackage account)?

Several days ago I discovered Travis ( http://travis-ci.org/ ) - nice open source build-service, easy to start and monitoring.
I've configured some github projects and add build status to it's readme. It's usable to know how is your haskell package building on separate fresh machine.

Following git-flow developing model there is a develop branch for snapshots and master branch for release. That why every commit in master branch should produce new release build ⇒ every commit in master branch should produce new hackage build upload. And also it will be nice to have that routine process done automatically.

It could be done using cabal-upload tool and --username and --password options. But it means that .travis.yml file should contain my hackage-password explicitly.
How can I avoid that?

-- 
Best regards,
dmitry malikov
!