Despite the advantages of decentralization and immutability, blockchain technology faces significant scalability and throughput limitations, which has prompted the exploration of off-chain solutions like payment channels. Adaptor signatures have been considered a promising primitive for constructing such channels due to their support for atomicity, offering an alternative to traditional hash-timelock contracts. However, standard adaptor signatures may reveal signer identity, raising potential privacy concerns. While ring signatures can mitigate this issue by providing anonymity, they often introduce high communication overhead, particularly in multi-account payment settings commonly used in UTXO-based blockchains like Monero. To address these limitations, we propose a Linkable Threshold Ring Adaptor Signature (LTRAS) scheme, which integrates the conditional binding of adaptor signatures, the multi-account payment of threshold ring signatures, and the linkability for preventing double-spending. The formal definition, security model and concrete construction of LTRAS are provided. We also analyze its security and evaluate its performance through theoretical analysis and experimental implementation. Experimental results demonstrate that our scheme achieve significantly lower computation and communication overhead compared to existing schemes in large ring sizes and multi-account payment scenarios. Finally, we discuss its application in cross-chain atomic swaps, demonstrating its potential for enhancing privacy and efficiency in blockchain transactions.

翻译：尽管区块链技术具有去中心化和不可篡改的优势，但其面临着显著的可扩展性和吞吐量限制，这促使了对支付通道等链下解决方案的探索。适配器签名因其支持原子性，被视为构建此类通道的有前景的原语，为传统的哈希时间锁合约提供了替代方案。然而，标准适配器签名可能泄露签名者身份，引发潜在的隐私问题。虽然环签名可以通过提供匿名性来缓解此问题，但它们通常会引入较高的通信开销，尤其是在基于UTXO的区块链（如Monero）中常用的多账户支付场景中。为了解决这些局限性，我们提出了一种可链接门限环适配器签名方案，该方案集成了适配器签名的条件绑定特性、门限环签名的多账户支付能力以及用于防止双花的可链接性。本文给出了LTRAS的形式化定义、安全模型和具体构造。我们还通过理论分析和实验实现，评估了其安全性和性能。实验结果表明，在大环规模和多账户支付场景下，与现有方案相比，我们的方案实现了显著更低的计算和通信开销。最后，我们讨论了其在跨链原子交换中的应用，展示了其在增强区块链交易隐私和效率方面的潜力。