# One-Time Password A one-time password or passcode (OTP) is an authentication value intended for one use or a short validity interval. ## Notebook evidence PDF page 61 of [[Scanned_20260730-1845]] expands OTP as “one time pass” beside an SMS short code and START/STOP/HELP commands. Page 62 continues into SIM acquisition, phone number, iCloud aliases, and recovery. ## Security boundary SMS OTP binds authentication to carrier and phone-number control and can be affected by number reassignment, SIM changes, forwarding, or account recovery. The notebook records the architecture; all codes and phone numbers remain redacted. ## Relationships [[Digital Identity]] · [[Account Recovery]] · [[Identity and Account Continuity]] ## Source - [[Scanned_20260730-1845]], PDF pages 61–62.