This post is older than a year. Consider some information might not be accurate anymore.
Git provides with the git bash and GUI a sufficient way to manage git repositories. Using git with SSH causes an error. Somehow git doesn’t take Putty’s plink. Well the culprit was a former installed program - tortoisegit. This article about Git on Windows fixed my problem with tortoisegit. Just set the
GIT_SSH environment variable to plink.