travis-senv is a utility to make it easier to move secure key files in and out of the Travis continuous integration environment. You can find the general instructions on secure environments on the Travis site, but this command takes care of splitting up larger files (e.g. SSH private keys) into multiple environment variable so that they fit into the keyspace.

It works as follwos:

• travis-senv encrypt ~/.ssh/id_deploy_dsa my_travis_envs will create a file called my_travis_envs that has the key/value pairs (suitably base64 encoded and chunked up)
• cat my_travis_envs | travis encrypt -ps --add while in the checked out repository you wish to add the secure keys to. This will modify the travis.yml file and add lots of entries to it.
• Within your Travis testing script, install the travis-senv command. I normally use it with an existing OCaml installation, but from scratch you just need these lines:

echo "yes" | sudo add-apt-repository ppa:avsm/ppa-testing
sudo apt-get update -qq
sudo apt-get install -qq ocaml ocaml-native-compilers camlp4-extra opam
export OPAMYES=1
opam init 
opam install travis-senv
eval `opam config env`

• Once that's done, just travis-senv decrypt > ~/.ssh/id_deploy_dsa and it will redirect its standard output to the file you specified.

You can even add multiple files to the same installation by using the -p <prefix> option to define a unique environment name for each file. It doesn't matter what the contents of the prefix is, as long as its a valid UNIX envvar character (i.e. alphanumeric is safest).