Abstract
We specify a personal-safety mobile application designed to be hard to repurpose as a surveillance tool. (1) An on-device software agent detects that its user has begun a trip, asks the destination, derives a route corridor and arrival window, and escalates through a graded ladder (query, visible cancel window, alert) on wide divergence or non-arrival. (2) The trip envelope is replicated end-to-end encrypted to designated family devices, each independently running the deadline timer and expecting a signed heartbeat with no location; deadline expiry or heartbeat loss raises the alarm on those devices, so destroying or jamming the phone triggers the alarm, with no server holding the clock or a key. (3) A duress code cancels visibly while still alerting the contacts. (4) Opt-in volunteers verified by proof of personhood may receive a nearby SOS; responses are logged, and a responder receives only a coarse position until accepted. (5) A short rolling window of raw location history is held by the contacts as ciphertext and released, under a directive the user wrote in advance, only on an alarm event plus a threshold of contacts. (6) Raw location expires on schedule; each day is summarised on the device into a coarse, owner-erasable list of places; a guardian receives alarms but never this history. (7) An anonymous gift delivery withholds the sender from the recipient, keeps the sender accountable to the system, enforces the recipient's blocks against the sender's true identity, and carries the recipient's optional thanks back.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Ly, Thon, "The Companion That Notices: A Personal Safety App with Agent-Initiated Journey Monitoring, a Serverless Dead-Man's Switch Run on Family Members' Devices, Duress Cancellation, Event-Triggered Release of Encrypted Location History, and Anonymous Gift Delivery with a Reply Channel", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/11975