Patent ID: 9602487
Date: 2017-03-21
CPC Classifications: H04L,H04W

Claim:
1. A method of a communications network for authenticating a transmitter device of the network to a receiver device of the network for a protected transmission of messages by the transmitter device to the receiver device and over the communications network, the transmitter device and the receiver device, the method comprising: generating, by the receiver device, a first code by applying a first common key to a random number; transmitting, by the receiver device, to the transmitter device, and in a synchronization message, (a) the random number and (b) a first partial code, wherein the first partial code is composed of a first subsection of, and extracted from, the first code; generating, by the transmitter device and using the first common key and the random number received from the receiver device, a second code, wherein a first subsection of the second code forms a second partial code and a second subsection of the second code forms a first counter; determining, by the transmitter device, whether the second partial code matches the received first partial code; generating, by the transmitter device and using the first counter and the first common key or a second common key, a third code, wherein a first subsection of the third code forms a third partial code; conditional upon a result of the determination being that the first and second partial codes match, transmitting, by the transmitter device and to the receiver device, a data message that includes useful data, a first partial counter formed of a subsection of the first counter, and the third partial code; generating, by the receiver device and using the first partial counter and the first common key or the second common key used by the transmitter device to generate the third code, a fourth code, wherein a first subsection of the fourth code forms a fourth partial code; and comparing, by the receiver device, the fourth partial code to the third partial code to verify the transmitter device and the transmitted data message.