Method and System for Cryptographically Demonstrating Continuous Offline Operation of a Sovereign Computing Device Across a Specified Interval Without Reliance on a Network-Connected Verifier.

Proves a sovereign device was offline for a stated interval, verifiable from the device public key alone with no network in the trust path. 35 claims.

A continuity ledger maintained on the operator device producing at a fixed cadence a heartbeat record containing the device hardware root-of-trust quote, a hash of all kernel-observed network-interface state, a hash of the immediately preceding heartbeat, a monotonic counter rooted in tamper-resistant hardware, a hardware-attested UTC timestamp, and a post-quantum module-lattice signature under a device key fuse-bound to the hardware root-of-trust. The unbroken sequence is the demonstrator artefact, verifiable offline by a third party holding only the device public key. Defended against existing remote-attestation protocols (TCG TPM 2.0 remote attestation, Intel SGX DCAP/EPID, AMD SEV-SNP attestation, Intel TDX attestation, ARM CCA attestation) which require a network-connected verifier and a certificate authority in the trust path (defeating the offline guarantee they are intended to prove), against tamper-evident logging (Auditbeat, AWS CloudTrail Lake immutability, IMA/EVM, splunk-style append-only logs) which requires a remote sink, against UEFI Secure Boot and TPM measured-boot which prove a one-shot state not interval continuity, against time-stamping protocols (RFC 3161, RFC 5816) which assume a TSA in the trust path, and against transparency-log protocols (Certificate Transparency, Sigstore Rekor) which require a public log endpoint. Filed 25 June 2026 as GB2615043.3.