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NIST 800-171 R-3.5.5

Prevent Reuse of Identifiers

Official citation: 3.5.5

Class: core · Severity: low

Statement of the obligation — verify against source

3.5.5

What it means

Don't reassign a previously used identifier — individual, group, role, or device — to a different user, group, role, or device for a defined period. This prevents the confusion and mistaken authorizations that can come from recycled identifiers.

Educational reference only — not legal advice. Consult a qualified assessor or attorney for binding compliance determinations.