Undefined lifecycle state identifier for managing security of an integrated circuit device

This document describes methods and systems that use an undefined lifecycle state identifier to manage security of a system-on-chip (SoC) integrated circuit (IC) device (102). As part of the described techniques, the SoC IC device (102) may include a first set of logic integrated circuitry (122) that determines that a first combination of bit values (312) fails to correspond to a known lifecycle state identifier. The first set of logic integrated circuitry (122) may then provide, to a second set of logic integrated circuitry (120), a second combination of bit values (402) that corresponds to the undefined lifecycle state identifier. The second set of logic integrated circuitry (120) may then place the SoC IC device (102) into an undefined lifecycle state (404).