I have a amazon EC2 instance with debian 6.0 installed. I am using SFTP via SSH to transfer fileles to my sever. But With root key all the folders from server are exposed. How can I generate different keys/users which who have access to certain folders on server. I don't want to use plain ftp for security reasons. Can we achieve this with User groups on amazon and by generating different keys?
You should use vsftpd. It can be secured without providing a shell account to users, which is what you would have to do if you wanted to run vsft over ssh. It accomplishes this with SSL certificates. Also, it easily provides for anonymous and?or autehnticated downloads, and chroot jails. You can find guides to its configuration all over the Net, but I found the Ubuntu man page particularly clear to read.