Yuri Borges Martins

18 · Brazil · Building open-source tools for content authenticity

I build software that proves things are real.

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What I'm doing now

• Building TrueShot, cryptographic photo verification for any Android device

• Writing a paper on sensor-based screen recapture detection for IEEE WIFS 2026

• Starting Computer Engineering in Granada, Spain (Fall 2026)

• CTO at Amrntech, GovTech company building software for municipalities and state governments across Brazil

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TrueShot, proving photos are real

An open-source Android camera that embeds cryptographic proof of authenticity in every photo. C2PA-inspired content provenance for the 3 billion devices that flagship-only solutions ignore.

Cryptography Signing ECDSA P-256 via hardware Keystore Hashing SHA-256 of JPEG bytes Attestation Validated against 3 Google Root CAs Timestamps RFC 3161 TSA + NTP anchoring Identity CAWG X.509 assertions

Novel research contributions Screen detection Sensor-based, not visual, no published precedent Corroboration Cross-device matching without communication Sensors 14 physical sensors at capture time Depth DEPTH16 integration when hardware supports Privacy Zero analytics, zero cloud, zero tracking

Screen recapture detection results (Redmi Note 11S)

Scenario	Score	Flagged?
Normal photo (daylight)	20	No
Normal photo (dark room)	30	No
Screen capture (daylight)	70	Yes
Screen capture (dark room)	85	Yes

Minimum 40-point separation. Threshold: 60. Purely sensor-based, no ML, no image analysis.

Source Code · Web Verifier · Threat Model · Changelog

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Tech

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