An electronic signal transmission device comprises a first communication
section to be connected to a first electronic device of a signal
transmitting side; a second communication section to be connected to a
second electronic device of a signal receiving side; an authentication
section for executing an authentication process with the first electronic
device and supplying key information for decryption; a decryption section
for executing a decryption process of an encrypted signal supplied from
the first electronic device based on the key information from the
authentication process; and a supply section for directly supplying the
encrypted signal from the first electronic device and the key information
to the second communication section in order to avoid signal delay by the
authentication.