This is a guide to zero security in linux. It is applicable only in places where security is not a threat and there is no threat from external networks.
The following options would allow a system running ssh to have a user with empty password so that you can use this user to login without any password or ssh keys.
I am adding a test user for this purpose.
passwd -d noneknowme
Configure ssh server to allow empty passwords.
Edit the following line in /etc/ssh/sshd_config
Restart sshd using /etc/init.d/sshd restart
Now you should be able to access the host with ssh with username noneknowme without any issues.
ssh -l noneknowme test
Don't try this . I am using this as a reference. Thanks to linuxquestions.org