LTRAS: A Linkable Threshold Ring Adaptor Signature Scheme for Efficient and Private Cross-Chain Transactions

2026-02-05

AI Summary

This work proposes Linkable Threshold Ring Adapter Signatures (LTRAS), a novel cryptographic primitive that integrates linkability, threshold mechanisms, and adapter signatures to address critical limitations in cross-chain transactions. Existing adapter signatures risk identity leakage, while conventional ring signatures incur prohibitive communication overhead in multi-account settings, making it challenging to simultaneously achieve privacy, efficiency, and double-spending prevention. LTRAS enables anonymous multi-account aggregation, provides strong anonymity guarantees, and supports double-spending detection through its inherent linkability. By formalizing a rigorous security model and devising an efficient cryptographic construction, LTRAS significantly reduces both computational and communication costs even at large ring sizes. The scheme is successfully instantiated in cross-chain atomic swaps, demonstrating its practicality and effectiveness in real-world decentralized applications.

Technology Category

• Multiagent Systems: Mechanism Design
• Game Theory and Economic Paradigms: Mechanism Design
• Natural Language Processing: Machine Translation, Multilinguality, Cross-Lingual NLP

Application Category

• Security and Privacy: Blockchains and distributed ledgers
• Economics, Online Markets and Human Computation: Economic aspects of blockchain and cryptocurrencies
• Search and Retrieval-Augmented AI: Multilingual and cross-lingual Web search

Abstract

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.

Problem

• adaptor signature
• ring signature
• privacy
• cross-chain transaction
• double-spending

Innovation

• Adaptor Signature
• Threshold Ring Signature
• Linkability
• Cross-Chain Atomic Swap
• Privacy-Preserving Blockchain