Patent ID: 8184812

Claim:
A secure computing device which produces a monotonic count value in response to a read operation, said device comprising: a counter configured to count in response to a count signal and to provide least significant bits of said monotonic count value; a roll-over detection circuit coupled to said counter and configured to detect advancement of a value presented in said least significant bits beyond a maximum value; a tamper detection circuit coupled to said roll-over detection circuit, said tamper detection circuit being configured to declare a security breach in response to detection of a roll over in said least significant bits of said monotonic count value; a register of at least one one-time-programmable bit configured to provide one or more most significant bits of said monotonic count value; and a synchronizer coupled to said counter and to said register, said synchronizer being configured to supply both of said least significant bits of said monotonic count value and said one or more most significant bits of said monotonic count value in response to said read operation.