Which of the following do not support encrypted data transmissions?

A.
Ethernet devices

B.
Infrared devices

C.
Wi-Fi devices

D.
Bluetooth devices

Explanation:
The infrared devices do not encrypted data transmission.
Infrared technology uses invisible infrared radiations to transmit signals to short distances. There are
two types of communication possible:
one in which the sender and the receiver are visible to each other and are situated in a straight line.
This is known as line-of-sight mode; the other type of communication known as diffuse mode does
not require the sender and receiver to be directly visible to each other. This technology is used in TV
sets, cordless microphones, laptops, remote modems, printers, and other peripheral devices.
Answer options D, A, and C are incorrect. The Bluetooth, Ethernet, and Wi-Fi devices supports
encrypt data transmissions.
Reference:
TechNet, Contents: “Wireless Networking”