Does github require all cloning, of both public and private repositories, to use an SSH public key? Maybe a better question, is can git clone a github repo without a ssh key at all.
You can use https protocol, as mentioned in "GitHub - Https access".
You would then use your GitHub login/password in a ~/.netrc file (which can be a security concern).
Note: on Windows, that would be an _netrc file.
Since GitHub supports smart http protocol (as detailed here), you can use that for cloning/pulling and for pushing.
SSH Key is used for more safety communication. Is not necessary, although using SSH Key is usefull because encrypte communication and also does not involve password.
No. A SSH key is only needed to push to a public repo on github, not to pull from one (although the easiest method to get a clone you can later push to uses the same key to pull as to push, that isn't the only way to work).
来源：https://stackoverflow.com/questions/7502247/is-an-ssh-key-required-to-clone-a-public-github-account