IRLid - Proof of Personhood

IRLid enables two individuals to generate cryptographic proof that they have physically encountered one another. The protocol relies on ECDSA signatures exchanged between the participants’ smartphones, producing a receipt that attests to the meeting without storing personal data on a server. Because the exchange is performed locally, the system does not require a dedicated application, biometric sensors, or a central authority to validate the interaction.

The workflow consists of each user scanning a QR code or similar token presented by the other party, after which the devices compute and exchange signed messages. The resulting receipt can be verified by any third party that possesses the public keys, confirming that the two parties were co‑present at the time of the exchange. This design makes the tool suitable for developers who need a lightweight, privacy‑preserving method of establishing real‑world presence in their applications.

IRLid is positioned as an experimental developer‑oriented solution for proof‑of‑personhood scenarios, offering a simple, cryptography‑based alternative to traditional CAPTCHAs that rely on online interaction. Its minimal requirements—just two phones and a brief scan—make it easy to integrate into services that must confirm physical meetings without exposing user data.