I heard that there was a public URL for all users on github where you can access their public keys or they can supply that URL of all their public keys. Is this true? If so what is that URL. Does it exist for bitbucket as well?
You can get with:
curl https://github.com/<username>.keys
Replace <username> with the actual username of the GitHub user.
This is useful when you set login permission to other servers. Just save its output into ~/.ssh/authorized_keys. To append it to the end from the command line:
curl https://github.com/<username>.keys | tee -a ~/.ssh/authorized_keys
It can also be done using Github API
curl -i https://api.github.com/users/<username>/keys
For bit bucket you can use the following: (This call requires authentication.)
curl -i https://bitbucket.org/api/1.0/users/<accountname>/ssh-keys
GPG public keys are now available at https://github.com/<username>.gpg
来源：https://stackoverflow.com/questions/16158158/what-is-the-public-url-for-the-github-public-keys