How did you create your keys?
With cygwin git or with mingw git in git bash?
, , cygwin ssh .ssh /home/name/.ssh mingw git ssh .ssh c:/user/name/.ssh
, .
cygwin.ssh -i ssh /home/name/.ssh/config.
, :
Host github.com
User jerryasher
Hostname github.com
IdentityFile c:/Users/jerry/.ssh/id_rsa
, mingw git git bash, cygwin git rxvt github.