Avionic equipment with single use signing of a transmitted message and associated avionic system, transmission method and computer program

An avionic equipment unit, intended to be on board an aircraft, the avionic equipment unit comprising:

• a processor for calculating a signature associated with a data field, the calculated signature depending on the data field;
• and
• a transmitter configured to transmit a message to another avionic equipment unit on board the aircraft, the message including the data field and the associated signature calculated by said processor,
• wherein the calculated signature further depends on a preceding signature associated with the data field of a last message transmitted by said transmitter, such that the calculated signature is unique for each data field and for each message transmitted by said transmitter.