Apparatus and a method for ciphering messages in mobile telecommunications
system user equipment are disclosed. The apparatus is arranged to receive
ciphering configuration parameters in a Radio Resource Control (RRC)
layer; forward ciphering configuration parameters to a Radio Link Control
(RLC) or Medium Access Control (MAC) layer; and, in response to
subsequent receipt of a message from the network, which message indicates
that the user equipment device is to start ciphering, configuring the
user equipment device to start ciphering using the ciphering
configuration parameters in the RLC/MAC layer.