US 11,792,007 B2
System and method for a vehicle network
Venkata Kishore Kajuluri, Southgate, MI (US); Xin Ye, Farmington Hills, MI (US); Bradley Warren Smith, Ann Arbor, MI (US); and Jacob David Nelson, Westland, MI (US)
Assigned to Ford Global Technologies, LLC, Dearborn, MI (US)
Filed by Ford Global Technologies, LLC, Dearborn, MI (US)
Filed on Mar. 17, 2021, as Appl. No. 17/203,775.
Prior Publication US 2022/0303134 A1, Sep. 22, 2022
Int. Cl. H04L 9/32 (2006.01); G06F 7/58 (2006.01)
CPC H04L 9/32 (2013.01) [G06F 7/588 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A system, comprising a computer including a processor and a memory, the memory storing instructions executable by the processor to:
monitor an onboard communication network of a vehicle to detect a plurality of available messages that include respective cipher-based message authentication codes (CMAC) and that were identified as eligible messages based on having a number of bits in the respective message that cannot be determined before the message is sent greater than a specified threshold;
select a first message from the plurality of available messages;
upon determining a length of the CMAC of the selected message is less than a length of a seed value specified by a random number generator that outputs a random number, select a second message from the plurality of available messages;
generate an updated CMAC by combining the CMAC of the second message and the CMAC of the first message;
input the updated CMAC into the random number generator based on determining a length of the updated CMAC is equal to the length of the seed value; and
then output the random number.