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 secondlayer 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 noncustodial wallets while exploring decentralized blockchain aspects.