I wanted to have multiple rsa keys for various different hosts to help prevent hidden connection issues.
Issues may arises when an rsa key is changed on one host that may have been used on another host effectively severing the connection without your knowledge.
By having different rsa keys when dealing with a host that is critical, one may prevent this.
The ~/.ssh/config file (on your local machine) can be edited so that it will refer to different ssh keys for different hosts.
Open the ~/.ssh/config file in a plain text editor. Then make modifications like this:
... # RSA Key for all accounts not specified below Host * IdentityFile ~/.ssh/id_rsa # RSA Key for DigitalOcean account Host *.digitalocean.* IdentityFile ~/.ssh/digitalocean_rsa
Note that these are NOT the public key but the private key.
Save the file and now you computer will use the appropriate key when visiting a host.