How to add SSH Key in Travis CI?

Using SSH keys is only available for private repositories on travis-ci.com (paid plans).

With the travis command line tool you can generate a new SSH key which will be set up on both Travis CI and your GitHub user account (if you use a dedicated GitHub user for Travis CI).

Here are the necessary console commands:

# Install Travis command line tool
gem install travis

# Login to Travis Pro (private repositories) account
travis login --pro

# Generate and setup SSH key for your GitHub repository
travis sshkey --generate -r organization/repository

Instead of generating a new SSH key with travis, it's also possible to upload an existing SSH key with:

travis sshkey --upload "C:\my_keys\id_rsa" -r organization/repository

Once the SSH key has been created, it is recommended that this key will be refrenced from the config file in the .ssh directory of your Travis user. You can do this by adding these lines to your .travis.yml:

# http://docs.travis-ci.com/user/build-lifecycle/
before_script:  
  - echo -e "Host github.com\n\tHostName github.com\n\tUser git\n\tIdentityFile ~/.ssh/id_rsa\n" >> ~/.ssh/config

For more information, here is a link to the official documentation: Generating a new key.

This feature is only available for private repositories currently.

For public repositories, you shouldn't need them to be private Git URLs (assuming they're on GitHub), so changing the URLs to use public clone URLs should do the trick.