Iain D. Stewart | Search arXiv

arXiv2026

Compact Shielded CSV: Post-Quantum, Private, Lightweight Client-Side Validation Blockchain

We propose Compact Shielded CSV, a private client-side validation blockchain for peer-to-peer payments designed for the postquantum era. Upgrading existing blockchains to quantum-resistant cryptography substantially increases on-chain overhead. By keeping all large cryptographic artifacts off-chain, Compact Shielded CSV keeps a minimal on-chain footprint independent of the size of the underlying cryptographic proofs and signatures. For a single input transaction, the onchain footprint is just 3 hashes (3x32 bytes): a nullifier, a degriefer, and a commitment to the transaction. We introduce the degriefer - a novel mechanism that enforces ownership and prevents double-spending using only hash commitments, eliminating the need for on-chain signatures entirely. These properties make Compact Shielded CSV a promising foundation for private, scalable, post-quantum digital payments.

cs.CR↗

arXiv2025

Satellite-derived Land Surface Temperatures Strongly Mischaracterise Urban Heat Hazard

Escalating urban heat, driven by the convergence of global warming and rapid urbanization, is a profound threat to billions of city dwellers. The science directing urban heat adaptation is strongly influenced by studies that use satellite-based land surface temperature (LST), which is readily available globally and address data gaps in cities, particularly in the Global South. LST, however, is a poor surrogate for near-surface air temperature, physiologically relevant human thermal comfort, or direct human heat exposure. This flawed practice leads to issues for several downstream use cases by inflating adaptation benefits, distorting the magnitude and variability of urban heat signals across scales, and thus misguiding urban adaptation policy. We argue that satellite-based LST must be treated as a distinct indicator of surface climate, which, though relevant to the urban surface energy budget, can be frequently decoupled from human-relevant thermal impacts especially during daytime. Only by a disciplined application of this variable, combined with complementary datasets, process-based and data-driven models, as well as interdisciplinary collaboration, can urban adaptation design and policy be effectively advanced.

physics.ao-ph↗