Ciphering switched off

I have a sony ericsson T68i mobile phone, got a new connection, but recently it has been displaying a message called “ciphering switched off” . I can make calls but each time some one picks the phone at the other end the above message is displayed he/she can hear me but I cant hear any1 .
I have tried a master reset but to no avail, I showed it to a few people also but they had no clue, The network is also fine….

Please I shall be very thankful if any one can be off help or can ask the sony ericsson vendors abroad how to rectify this problem.

Cheers in advance.
PKC

I assume you live in a third world country. See :

It pretty much means that your phone is ready to be hacked and somebody's probably listening in!!!

Just kidding! It just means that there's no encryption, so its better to not do any data transfers. For voice, it doesn't make a difference. All cell phone conv are dangerous anyway.!
HA!