GitHub distributes a simplified git client for Windows they call GitHub for Windows; it authenticates via GitHub account, and although it usually uses SSL authentication for local repositories it creates, if you tell it to use an existing local repository that has an SSH remote on GitHub it will use your GitHub credentials to set up an SSH key on the GitHub account for itself. But where does it keep the SSH key in the filesystem?
%HOMEDRIVE%%HOMEPATH%\.ssh\id_rsa.pub is where the key is
On my work PC it is in %USERPROFILE%/.ssh/ and not %HOMEDRIVE%%HOMEPATH%/.ssh/.
On many computers those folders are the same location, but it depends on the configuration. So it seems %USERPROFILE% is the location used by GitHub for Windows, which is also the ~ home location for its Git-Bash.
This is confusing since my Windows-Git default installation uses %HOMEDRIVE%%HOMEPATH% as its ~ home location.
The default location is: %HOMEDRIVE%%HOMEPATH%\.ssh\id_rsa.pub. That would expand to something like C:\Users\dennis\.ssh\id_rsa.pub
If %HOMEDRIVE%%HOMEPATH%\.ssh\id_rsa.pub already exists, github creates a key named github_rsa(.pub) in the same folder.
It's in %HOMEDRIVE%%HOMEPATH%\.ssh
Note that GitHub for Windows normally uses SSL; SSH keys won't have been created unless you've used an SSH repository with it at some point.
On my Windows 10 Home the .ssh folder's path is %HOMEDRIVE%%HOMEPATH%\AppData\Roaming\SPB_Data\.ssh
来源：https://stackoverflow.com/questions/20226147/where-does-github-for-windows-keep-its-ssh-key