A passive, batteryless tamper-evidence seal carrying an unclonable resonance fingerprint that breach annihilates — not alters.
Interrogate the seal for a match. Then choose an attack vector and watch the resonance fingerprint collapse — irreversibly. Apply a new seal and a different fingerprint enrolls. No two alike.
Sphragnil's novelty is not in software or in a printed code. It is in the physics of the seal body itself — and in one coupling that makes the credential self-erasing.
The fingerprint is a spectrum of resonances set by uncontrolled manufacturing scatter — a physical unclonable function. It is not a stored number and cannot be predicted from the design. No two seals share it.
// stochastic structure → unique spectral identityApplied to a boundary, the body is locked in a metastable state — elastic energy stored under tension, in a buckled element, or in a balanced-stress laminate. The enrolled fingerprint is a property of that loaded state.
// metastable geometry → energy stored at applicationCut, peel, lift, delaminate, drill, heat, or solvent it — every path releases the stored strain and drives the body through an irreversible collapse. The fingerprint is destroyed, not shifted to a value an adversary could anticipate.
// breach → strain release → signature annihilatedIdentity and integrity ride on the same physical signature, so a single read settles both. There is nothing to power, nothing to print, nothing subjective to inspect.
The applied seal is interrogated and its fingerprint reduced to a reference vector, cryptographically bound to the asset record so it cannot be silently reassigned.
An acoustic ping or an RF backscatter sweep recovers the fingerprint. All energy comes from the reader — fixed at a gate, handheld, or carried on a patrol route.
A match within tolerance proves both, because a breach would have destroyed the very fingerprint being matched. No match, or no signal, means breach, substitution, or removal.
No secret is stored in the seal. The reader supplies all energy; the registry holds only a signed reference.
The seal is built so the plausible ways to defeat the boundary all act through the strain store. Cut it, peel it, drill it, heat it, dissolve it — each path, by different physics, releases the stored energy and destroys the fingerprint. There is no low-energy route that defeats the boundary and leaves the signature intact.
The fingerprint's strength comes from stochastic parameters that stack into a high-entropy identity — and from the fact that the identity is a physical resonance of a unique body, not a value that can be recorded and played back.
Dimensional and material scatter set where each resonance lands — the primary entropy source.
// per-mode · several bits eachCoupling and damping scatter add discrimination and a liveness check at read time.
// secondary entropy · anti-spoofThe joint geometry fixes relationships a single-channel spoof can't reproduce.
// resists partial emulationThe stochastic yield of resonant elements sets the fingerprint's dimensionality.
// dimensionality of vectorA multimodal body adds an independent acoustic-or-RF channel, multiplying total entropy.
// multimodal · cross-validatedTens of bits in a single-channel body; substantially more multimodal — collisions are negligible.
// brute-force emulation infeasibleThe attack that defeats adhesive and tag seals can't work here: detachment itself relaxes the strain store and destroys the fingerprint. A reapplied seal can't match.
The credential is a physical resonance of a body that no longer exists after breach. A recording can't recreate it, and the unknown stochastic spectrum can't be emulated.
Void labels and holograms can be copied. Powered sensors and electronic PUFs can be replayed. Chipless tags survive the breach they are meant to prove. Sphragnil is the only one that is unclonable, passive, and self-erasing at once.
| Property | Void label | Hologram | Powered sensor | Electronic PUF | Chipless / SAW | Sphragnil |
|---|---|---|---|---|---|---|
| Unclonable identity | no | no | partial | yes | partial | yes |
| Passive · batteryless | yes | yes | no | no | yes | yes |
| Resists replay / re-apply | no | no | no | no | no | yes |
| Self-erasing on breach | tears | no | no | no | survives | yes |
| Machine-verifiable | visual | visual | yes | yes | yes | yes |
Prove a carton or container closure was never opened in transit, with per-unit identity for track-and-trace and machine verification at receiving.
Controlled substances, munitions, and sensitive assets — custody that resists the substitution and replay attacks that defeat visual and loop seals.
An objective, unclonable, breach-erasing integrity proof — each contactless read extends a cryptographically bound custody trail; a breach terminates it.
Per-container unique, publicly verifiable integrity evidence for ballot boxes and transfer containers that cannot be reproduced once breached.
Across a panel-door seam, meter cover, or calibration enclosure, it evidences physical access independently of the equipment's own electronics.
A fixed or mobile reader interrogates a population of seals on a route, logging every match and flagging any non-match in one pass.
The claim set is narrowed where it is defensible: the coupling of a stochastic, physically unclonable spectral identity to a strain-stored frangibility that breach destroys irreversibly. As an article of manufacture and a method of physical transformation, the subject matter sits clear of abstract-idea exposure.
Independent claims span the article, authentication method, manufacture & enrollment, the system, the applicator and kit, the passive reader, and the chain-of-custody method — covering acoustic, RF, and multimodal embodiments; pre-tension, bistable snap-through, and residual-stress laminate strain stores; and post-breach decorrelation so a breached seal yields no replayable target.
