Server Auth, pls help!

Hello! at first, sorry for my bad English

I have MC server with bukkit, and server flag "online-mode" changed "false" (in server.properties)
So, any players, can change his nick in hex-editor, and get admin(or "op") permissions on server
example: in ops.txt exist string "qwerty", and user "qwerty" have admins permissions, but any user can login for this nick

how can I solve this problem?
are there special plug-ins?
I hope ,I described the problem clearly, thanks in advance

 

http://plugins.bukkit.org/#ti=offline authentication&ta=all&au=&subm=false&pno=0

 

The best solution is to change your game mode to online mode so players can't do that

 

thanks, and do i understand, that after instal and config auth plugin, any player can not login in server under my name and with my permissions, even if they changed their name in hex-edit ?

 

That is correct.

 

nice! )))