Should I publish my public SSH key with user@hostname at the end?

Question

In ~/.ssh/id_rsa.pub my public key is stored as:

ssh-rsa magicmagicmagicmagic...magicmagic username@hostname

When publishing my public key, should I include the username@hostname bit? Can I replace it with something else? My concerns are that:

• I may want to change the label for vanity purposes (super@wishihadbetterhostname) - but I don't want to mess things up by doing this (for example, if a common tool assumes this convention is upheld)
• I'm concerned that I'm making it that much easier to get onto my machine by giving away my username and hostname!

Answer 1

The user@hostname part is just a comment, you can set your own comment by using the -C option or for existing keys change it with -c (http://man7.org/linux/man-pages/man1/ssh-keygen.1.html) changing it will not affect your key, so yes, you can change it to superduperuser@somfancehostname.

Snippet for these ssh-keygen options:

 -C comment
         Provides a new comment.

 -c      Requests changing the comment in the private and public key
         files.  This operation is only supported for RSA1 keys.  The
         program will prompt for the file containing the private keys,
         for the passphrase if the key has one, and for the new comment.

For instance,

You'd simply do ssh-keygen -C [email protected] and that results in the following: