Scriptless cross-chain deferred asset transfer for AIoT

In AIoT service scenarios such as sensing-as-a-service and edge AI outsourcing, a service requester may need to establish a payment commitment before service execution, while final transaction should be deferred until service delivery is verified. When the requester and the provider hold assets on different blockchains, this requires a cross-chain deferred asset transfer. Existing cross-chain protocols focus on immediate transaction. Adaptor-signature-based swaps assume that once a linked transfer completes, the secret becomes immediately usable; deferred transaction requires the adaptor secret to remain unavailable even after the binding has been established. We propose a scriptless cross-chain deferred asset transfer protocol based on a delayed timed atomic lock (DTAL) construction. DTAL introduces a delayed adaptor secret mechanism that preserves atomic binding between two cross-chain transfers while preventing the secret from being used before a predefined release time. It is instantiated using two-party adaptor signatures, time-release encryption, and verifiable timed discrete logarithm. The underlying blockchains only need to validate ordinary transactions and signatures. Security analysis shows that the proposed protocol achieves atomicity and timeout safety. Experimental results demonstrate low running time and communication overhead while reducing gas costs compared with contract-based cross-chain approaches.