A transmitting device encrypts DMR voice superframes using encryption parameters and sends the encryption parameters in at least one of the voice superframes by: identifying a selected number of bits from a plurality of vocoder frames the voice superframe; replacing each of the identified bits with a corresponding bit of a first encryption parameter; placing at least one encryption parameter in an embedded signaling field of the voice superframe; and transmitting the voice superframe with the encryption parameters to a receiving device. The receiving device extracts the encryption parameters, which can be a key identifier, an algorithm identifier, and an initialization vector for use in decrypting messages from the transmitting device.