Patent ID: 6986057

Claim:
A method of device authentication, the method comprising: receiving, at a printer cartridge comprising a roaming device, a challenge from a host printer device; generating, at the printer cartridge comprising the roaming device, a first nonreversible computation result, wherein the first nonreversible computation result is computed by seeding a first nonreversible algorithm with at least the challenge, and a roaming device secret; outputting to the host printer device a response to the challenge, wherein the outputted response includes the first nonreversible computation result, outputting to the host an identification and at least another data item; generating, at the host printer device a second nonreversible computation result, wherein the second nonreversible computation result is computed by seeding a second nonreversible algorithm with at least a challenge and a host printer device secret; comparing, by said host printer device, said fast nonreversible computation and said second nonreversible computation in order to authenticate the printer cartridge comprising the roaming device; allowing said host printer device to print documents if said printer cartridge comprising said roaming device is authenticated.