原文地址：http://superuser.com/questions/397288/using-cygwin-in-windows-8-chmod-600-does-not-work-as-expected
Try running:
chgrp -R Users ~/.ssh
The longer explanation is for some reason, cygwin’s /etc/passwd / /etc/group generation are putting the user’s default/main group as None. You cannot change the permission of None, so the chmod for group has no effect. I didn’t try repairing the passwd / group files myself, but I did a chgrp -R Users ~/.ssh (or the group “HomeUsers” On Windows8 pre-release). After that, you can do thechmod 0600 and it’ll work as expected. The chgrp to the Users group can be done in whichever other similar cases you find; it even works as expected since cygwin puts users in the Users group as a secondary group (instead of primary, which would be the correct behavior).