Adding an SSH key to GitHub (Linux)

Every time you access your GitHub repository, you must authenticate to make sure only you have access to the repository. There are a number of ways of authenticating with GitHub, but the most convenient way for this class is to use an SSH key. This page describes how to set up an SSH key on your computer and register this key with your GitHub repository. You will need to do this only once for the digital lab computers and for every other computer you intend to use to complete the assignments.

Create an ssh key by running the following command:

$ ssh-keygen -t rsa

Press enter to save the key pair into the default .ssh/ subdirectory in your home directory. You should see the following prompt:

Enter passphrase (empty for no passphrase):

It is easier (but less secure) to leave the passphrase empty by pressing enter for the default “no passphrase”. You should then see the following output:

Your identification has been saved in /your_home/.ssh/id_rsa.
Your public key has been saved in /your_home/.ssh/id_rsa.pub.
The key fingerprint is:
a9:49:2e:2a:5e:33:3e:a9:de:4e:77:11:58:b6:90:26 username@remote_host
The key's randomart image is:
+--[ RSA 2048]----+
|     ..o         |
|   E o= .        |
|    o. o         |
|        ..       |
|      ..S        |
|     o o.        |
|   =o.+.         |
|. =++..          |
|o=++.            |
+-----------------+

At this point you have a public and private key that you can use to authenticate. This key is stored in your CAEDEM file space and should be able to access this key on any of the digital lab computers. More details on how to do this can be found at the following tutorial.

After creating an ssh key, you will need to add your public key to your GitHub account. This will authorize you to access your remote GitHub repositories on your computer without authentication. You can manually print your public key to the terminal by executing the following command:

$ cat ~/.ssh/id_rsa.pub

You will need to copy this key and paste it into a web page as described below. Go to https://github.com/settings/keys, and add your key to your Github account using the New SSH key button. You can view your newly created key using cat ~/.ssh/id_rsa.pub, then simply copy and paste into Github as described above. The following GitHub tutorial provides more details on how to do this.