Bitcoin double-spending risk and countermeasures at physical retail locations

This research examines vulnerabilities and potential attacks using Bitcoin payment systems at physical retail locations. It also lays a theoretical and practical foundation for effective countermeasures that ensure the integrity of decentralized transactions and bolster the confidence of both merchants and customers. The study focuses on potential double-spend attacks, particularly in the context of instant payments made via non-custodial crypto wallets. It also evaluates alternatives for instant crypto payments that use alternative coins and second-layer blockchain solutions. Research has indicated that Eclipse, Sybil, Majority, Race, and Finney attacks carry a relatively low risk, especially when payment amounts are limited. The paper identifies Replace-By-Fee attacks as the most significant threat and presents a set of countermeasures. These findings are of great importance to cryptocurrency experts, payment tech researchers, retail enterprises, and stakeholders using non-custodial wallets while exploring decentralized blockchain aspects.