We are happy to announce that our paper “How To Make Delegated Payments on Bitcoin: A Question for the AI Agentic Future” has been accepted to Financial Cryptography 2026.

Abstract:

AI agents and custodial services are increasingly being entrusted as intermediaries to conduct transactions on behalf of institutions. The stakes are high: The digital asset market is projected to exceed $16 trillion by 2030, where exchanges often involve proprietary, time-sensitive goods. Although industry efforts like Google’s Agent-to-Payments (AP2) protocol standardize how agents authorize payments, they leave open the core challenge of fair exchange: ensuring that a buyer obtains the asset if and only if the seller is compensated without exposing sensitive information.

In this work, we introduce proxy adaptor signatures (PAS), a new cryptographic primitive that enables fair exchange through delegation while preserving atomicity and privacy. Our protocol allows stateless buyers to delegate payments securely without managing long-term cryptographic secrets, while guaranteeing fairness between buyers and sellers. We formalize PAS in a threshold setting and provide an efficient construction compatible with major blockchain systems including Bitcoin, Cardano, and Ethereum. A prototype implementation demonstrates strong practical performance.

More details can be found in the preproceedings version of the paper.