A process for transmitting encrypted data through a radio transmission channel having a frame structure such that a TDMA frame comprises at least time slots of a first type forming a traffic channel and at least one time slot of a second type forming an associated signaling channel, comprises steps according to which: a sequence of encrypted data packets is transmitted in the traffic channel on the basis of a determined time slot of the first type, whereas an associated cryptographic synchronization information cue is transmitted in the associated signaling channel inside a determined time slot of the second type, and a cryptographic synchronization delay information cue relating to the time gap between said determined time slot of the second type and said determined time slot of the first type, is also transmitted in the associated signaling channel.