Authentication packet for communications
The present invention is a communications system comprising a host device and an external device or product having a 4 byte Product ID. The host device is adapted to poll the external device to determine the Product ID of the external device. The external device is adapted to transmit its 4 byte Product ID to the host device in response to the Product ID Request from the host device. The host device is adapted to generate a packet having an authentication command 0×1 F followed by a pair of CRC bytes having a CRC_HI byte and a CRC LO byte. The pair of CRC bytes take into account the 4 byte Product ID and the authentication command 0×1 F when generating an overall value. The 4 byte Product ID is not contained in the packet. The host device 12 is further adapted to transmit the packet to the external device 14. The external device is further adapted to authenticate the packet, and if authenticated, provide the host device with full command and control of the external device 14. When authenticating, the external device knows and includes the fact that the value generated by the pair of CRC bytes has taken into consideration the value represented by the 4 byte Product ID.
1 . A communications system comprising: a host device and an external device; said external device having a 4 byte Product ID; said host device being adapted to transmit a Product ID Request to said external device; said external device being adapted to transmit said 4 byte Product ID to said host device in response to said Product ID Request from said host device; said host device being adapted to generate a packet comprising an authentication command followed by a pair of CRC bytes; said pair of CRC bytes are adapted to generate a check sum taking into consideration the value of said 4 byte PRODUCT ID even though said 4 byte Product ID is not in said packet; said host device being adapted to transmit said packet to said external device; said external device being adapted to authenticate said packet by taking into account that said check sum value generated by said pair of CRC bytes takes into consideration said value associated with said 4 byte Product ID; and if authenticated, to provide said host device with command and control of said external device.
2 . The system of claim 1 , wherein said packet further comprises a message byte having an authentication command of 0×1F and said check sum generated by said pair of CRC bytes takes into consideration the value of said 4 byte PRODUCT ID and said value associated with said authentication command of 0×1F.
3 . The system of claim 2 , wherein said host device is a communication device.
4 . The system of claim 3 , wherein said host device is a host computer system.
5 . The system of claim 4 , wherein said external device is adapted to support data exchange.
6 . The system of claim 5 , wherein said external device is an access control device for controlling access thru an entry way.
5 . A method for communicating between a host device and an external device to ensure that the host system is authorized to control the external device, the method comprising the steps of:
a) polling the external device for a 4 Byte Product ID;
b) transmitting said 4 Byte Product ID to the host device in response to said step of polling the external device;
c) building a packet comprising an authentication command;
d) generating a check sum value using a pair of CRC bytes based upon the values associated with both said authentication command and said 4 Byte Product ID;
e) transmitting said packet and said check sum value to said external device for authentication;
f) authentication of said packet by said external device taking into account that said check sum value was determined based upon both said authentication command and said 4 Byte Product ID; and
g) providing said host device with command control of said external device if said packet is authenticated.