Auth fails on Windows XP with git and tortoisegit

My authentication keeps failing. I've created my SSH keys and the public key has been imported by the local git admin, but I still get prompted for a password:

git.exe clone  --progress -v  "git@repo:project.git" "C:\web\project"  
Cloning into C:\web\project...  
git@repo's password:  
fatal: The remote end hung up unexpectedly

• My SSH keys are 开发者_Python百科passphraseless and live under "C:\Documents and Settings\username\.ssh" and I also copied them to "C:\Documents and Settings\username\ssh" (without the preceding dot) just for good measure.
• In the Windows environment variables screen, the HOME system var is set to the correct directory for my user.

What does ssh -vvv git@repo returns?

As long as this ssh request doesn't work, no git operation will work with the git@repo server.
And if the ssh reports it is does try to offer the publickey, then you must double-check it has been correctly added to the ~git/.ssh/authorized_keys file on the repo server.

Here is an extract of example of a ssh session which works:

debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug3: start over, passed a different list publickey,password,keyboard-interactive
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /p/.ssh/mypubkey
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug2: input_userauth_pk_ok: fp f8:d9:7...:cf

debug3: sign_and_send_pubkey
debug1: read PEM private key done: type RSA
debug1: Authentication succeeded (publickey).
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug1: Entering interactive session.

Two comments:

• My %HOME% reference not %HOMEDIR% but a custom drive (p:\), this is a local convention at work and might not apply to you.
• the names of my public/private keys don't follow the default standard (id_rsa.pub/id_rsa)

I have added a config file in the %HOME%\.ssh directory in order to name explicitly the public key file:

host gitrepo
     user git
     hostname repo
     identityfile ~/.ssh/mypubkey

That way, I can simply type: ssh gitrepo, and ssh will know which user, hostname and exact full path of the public key to use.