Patent ID: 8396985
Filing Date: 2013-03-12
Classification: H04L

Abstract:
1. A method of preventing replay attacks on a network processor coupled to a packet-switched network, the method comprising: initializing an anti-replay window for recording sequence numbers of received data packets; storing the anti-replay window in a security memory having R data words, wherein the anti-replay window has N bits, and wherein each of the R data words has a width W bits, where R, W and N are positive integers, and R*W=N; receiving a data packet having a sequence number appended to the data packet; determining whether the received sequence number is within a range of the anti-replay window, wherein the range of the anti-replay window is determined by a maximum sequence number of the anti-replay window and a minimum sequence number of the anti-replay window; i) if the received sequence number is within the range of the anti-replay window: ii) if the received sequence number is greater than the maximum sequence number of the anti-replay window range: updating the bit of the anti-replay window corresponding to the received sequence number to indicate that the sequence number is received; setting the word valid bit corresponding to the data word including the updated bit to indicate that the data word includes valid data; and