Set up SSH public key authentication

Before starting you should:

• Have WinSCP installed;
• Know how to connect to the server without public key authentication.

If you do not have a key pair yet, start with generating new key pair.

Connect to your SSH server using WinSCP with the SSH protocol, using other means of authentication than public key, e.g. typically using password authentication.

Once logged in, configure your server to accept your public key. That varies with SSH server software being used:

Navigate into the .ssh subdirectory of your account home directory. You may need to enable showing hidden files to see the directory. If the directory does not exists, you need to create it first.

Once there, open the file authorized_keys for editing. Again you may have to create this file if this is the first key you have put in it.

Then switch to the PuTTYgen window, select all of the text in the Public key for pasting into authorized_keys file box, and copy it to the clipboard (Ctrl+C). Then, switch back to the editor and insert the data into the open file, making sure it ends up all on one line. Save the file.

You may also need to ensure that your account home directory, your .ssh directory and file authorized_keys are not group-writable or world-writable.

Read more about changing permissions.

Save a public key file from PuTTYgen, and copy that into the .ssh2 subdirectory of your account home directory. In the same subdirectory, edit (or create) a file called authorization. In this file you should put a line like Key mykey.pub, with mykey.pub replaced by the name of your key file.

For other SSH server software, you should refer to the manual for that server.

When configuring session, specify path to your private key on SSH > Authentication page of Advanced Site Settings dialog.

Alternatively, load the private key into Pageant.

• Using Public Keys for Authentication;
• Using PuTTYgen;
• Understanding SSH Key Pairs.