1. A portable electronic device comprising: at least one processing unit; a computer readable medium, coupled to the at least one processing unit and encoded with: executable instructions, wherein the executable instructions are obfuscated that, when executed by the at least one processing unit, cause the at least one processing unit to implement an obfuscated state machine configured to authenticate a user of the portable electronic device at least in part in response to receiving a signal from a certifying authority separate from the portable electronic device; and an authentication key, wherein the authentication key is protected by the obfuscated state machine.