A Swiss Italian team pairs short range positioning radio with privacy preserving cryptography, betting it can anchor the EU's forthcoming digital identity wallet.
Europe is building a digital identity wallet that, by the end of 2026, every member state is supposed to offer its citizens. One of the open questions in that build is how to prove a person was physically present at a place, a hospital zone, a concert gate, a polling station, without the credential leaking identity or exact location. A patent application filed in April by The Hashgraph Group, a Swiss distributed-ledger engineering firm, and Truesense, an Italian sensor startup, is one of the first concrete technical proposals for how to do that, and it leans on a short-range radio already shipping in some smartphones and car keys.
The filing, lodged at the European Patent Office on 4 April 2026 as application EP26425032 and designating 44+ European countries, with a parallel U.S. application in process, names the system "Continuous Identity Trust Infrastructure," or CITI, according to a joint press release from The Hashgraph Group and Truesense. It is an application, not a granted patent, and the press release is the only public document describing the system. The underlying technical specification, performance numbers, and security claims have not been independently reviewed.
The proposal stacks three technologies. The first is ultra-wideband radio, a short-range positioning technology that can measure distance to a fixed anchor with centimeter-level precision, used today in AirTags, some car entry systems, and a growing number of phones. The applicants describe operating the radio in a "radar mode" that can also pick up breathing and heart rate. The second layer is a W3C-standard decentralized identifier, a string of characters that functions like a portable username, plus a "presence-binding token" stored in a digital wallet called IDTrust. The third is a zero-knowledge proof, a cryptographic trick that lets a third party confirm a statement is true without learning the underlying data. The combined output is a Verifiable Credential carrying a zone identifier, a timestamp, and a hash, anchored to a distributed ledger.
The distributed ledger in question is Hedera, a public network whose hashgraph consensus algorithm the Swiss firm already builds on. The Hashgraph Group's corporate site lists prior enterprise work in digital credentials, supply-chain traceability, and IoT, including deployments for KPMG and the Dubai International Financial Centre, though none of those customer programs involve CITI or ultra-wideband.
The filing lands inside an active European regulatory push. The eIDAS2 regulation, the legal basis for the EU Digital Identity Wallet, took effect on 20 May 2024 and obliges member states to issue certified wallets to citizens who want them by the end of 2026. The EU's broader digital identity infrastructure, the European Blockchain Services Infrastructure, is being upgraded to support these wallets. Two other regulations shape where proof-of-presence could matter: NIS2, the cybersecurity directive, and the Digital Product Passport under ESPR, which obliges manufacturers to track products through their lifecycle starting with batteries in 2027.
The applicants position CITI as infrastructure for several of those regimes. Hospital access control, concert and stadium entry, factory floor zones, and smart-city gates all appear in the press release as illustrative targets. A chemical-plant worker walking into a regulated area, a teenager buying alcohol, a refugee opening a bank account: the recurring scenario is a regulator wanting cryptographic evidence that a real body was present, without that evidence revealing who the person is or where exactly they stood.
The technical bet is that ultra-wideband can verify the body, not just the device, and that zero-knowledge proofs can strip the identity out of the location claim. Both bets are unsettled. Independent cryptographers have not yet examined the proposal, and the press release's claims about centimeter-level precision and on-device vital-sign machine learning are vendor assertions, not peer-reviewed results. The Truesense corporate site, in a brief check, returned only a cookie and consent banner; the company's prior ultra-wideband deployments and team beyond the CEO could not be independently corroborated.
The closest existing alternatives are simpler. Building access typically uses a card or phone tap. Age verification uses a digital identity wallet plus a photo match. Device attestation, a separate cryptographic mechanism, lets a phone prove it has not been tampered with, which is enough for many regulated workflows. Whether ultra-wideband plus a zero-knowledge proof adds enough to justify the cost and complexity, or whether it is the right primitive for the EU's emerging wallet, is a question the filing puts on the table rather than answers.
For regulators, the open question is whether proof-of-presence belongs in the EU Digital Identity Wallet at all, and if so, as a standard verifiable credential, a private-sector extension, or a regulated primitive. For builders, the open question is whether ultra-wideband is the right sensor for it. For the applicants, the open question is whether the patent, once examined, will cover a primitive broad enough to license, or a narrower implementation that competitors can route around. The European Patent Office's examination, not the filing date, is what will determine which.