Definition
QSECURITY is the system value that controls how strictly IBM i enforces access control and integrity protection. Level 20 requires a user ID and password but grants broad access by default. Level 30 requires specific authority to use resources. Level 40, the shipped default, adds integrity protection between system and user programs. Level 50 adds the strictest integrity enforcement and is required for C2, FIPS-140, and Common Criteria certification.
For buyers evaluating IBM i security software, the current QSECURITY level is one of the first things a security or MFA partner will ask about, because it determines how much work the underlying operating system is already doing versus how much add-on software needs to cover.