Reading quantum signals between Alice and Bob

Shelby Kimmel, Shimon Kolkowitz

We investigate the feasibility of quantum seals. A quantum seal is a state provided by Alice to Bob along with information which Bob can use to make a measurement, break the seal, and read the classical message stored inside. There are two success criteria for a seal: the probability Bob can successfully read the message without any further information from Alice must be high, and if Alice asks for the state back from Bob, the probability Alice can tell if Bob broke the seal without permission must be high. We build on the work of [Chau, PRA 2007], which gave optimal bounds on these criteria, showing that they are mutually exclusive for high probability. We weaken the assumptions of this previous work by providing Bob with only a classical description of a prescribed measurement, rather than classical descriptions of the possible seal states. We show that this weakening does not affect the bounds but does simplify the analysis. We also prove upper and lower bounds on an alternative operational metric for measuring the success criteria.

François Chapeau-Blondeau

William J. Richardson

Significant — Reading Spatial PTT Qudits In Sign Net From Alice To Bob. This important article defines a Bob-side reinflated-qudit straight reader for Spatial PTT transfer. Instead of sending a full finalized spatial qudit body, Alice sends a compact post-final 3D-to-2D address capsule and sign/check branch. Bob reinflates a comparable qudit structure, runs the declared straight-read breakdown code, and compares Bob’s compressed capsule against Alice’s sealed capsule while preserving sign custody, blanks, ordered history placeholders, and anti-flattening provenance. The Python v4 synthetic test reports fourteen expected classifications with zero unexpected classifications and an average transfer object of about 18.54 percent of the synthetic full qudit body.

Lei Wang, Jie‐Hui Huang, Jonathan P. Dowling +1 more

William J. Richardson

Foundational — 3 of 3. Reading Spatial And Superconductivity PTT Qudit Capsules From Alice To Bob. This article defines a general Alice-to-Bob endpoint Reader for PTT qudit capsules. The Reader unifies Spatial PTT and Superconductivity Materials-Qudit handoff under one endpoint engine: Alice exports a post-final capsule and sign/check branch, router carries the sealed package without payload authority, Bob reinflates a comparable shell, Bob runs straight breakdown, and the endpoint result is written by capsule-to-capsule comparison plus branch custody. Spatial and Materials-Qudit capsules use separate declared profiles, while EF1--EF3 Directional return fields remain Alice-authored upstream evidence that Bob may verify but may not reconstruct. The result is a reusable Reader layer that prevents separate Spatial and Materials readers, blocks Bob-side route authorship, and preserves endpoint verification as its own authority layer.