Windows 11 systems must use a BitLocker PIN with a minimum length of six digits for pre-boot authentication.

If data at rest is unencrypted, it is vulnerable to disclosure. Even if the operating system enforces permissions on data access, an adversary can remove non-volatile memory and read it directly, thereby circumventing operating system controls. Encrypting the data ensures that confidentiality is protected even when the operating system is not running. Pre-boot authentication prevents unauthorized users from accessing encrypted drives. Increasing the pin length requires a greater number of guesses for an attacker.