
Briefing
Constructing efficient aggregate signatures under standard assumptions without the random oracle model, especially with ordered properties, presents a core research problem. This paper proposes a new ordered multi-signature scheme with public-key aggregation, achieving security under the SXDH assumption and eliminating reliance on the random oracle model. This breakthrough significantly reduces storage and verification overhead for multi-party authenticated transactions, paving the way for more scalable and secure decentralized architectures.

Context
Prior to this research, aggregate signature schemes, while offering efficiency benefits by compressing multiple signatures, often relied on strong cryptographic assumptions or the heuristic random oracle model for their security proofs. This presented a theoretical limitation for their deployment in environments demanding rigorous security guarantees, particularly when verifying the specific order of signers was also a requirement.

Analysis
The paper introduces an ordered multi-signature scheme, a new cryptographic primitive building upon sequential aggregate signatures. This scheme fundamentally differs from previous approaches by incorporating a public-key aggregation property, which allows a list of multiple public keys to be compressed into a single, short aggregated key. The core mechanism involves a modification of existing sequential aggregate signature designs, ensuring that the order of signers can be verified while maintaining a compact signature size.
Crucially, its security is formally proven under the Symmetric External Diffie-Hellman (SXDH) assumption, operating within the standard model and thus avoiding the less rigorous random oracle model. This ensures a higher level of cryptographic assurance for its practical deployment.

Parameters

Outlook
This research opens new avenues for highly efficient and cryptographically robust multi-party authentication in distributed systems. Future work will likely explore optimizing the scheme’s computational performance for real-world blockchain applications, potentially integrating it into light client protocols or cross-chain communication mechanisms where compact proofs are paramount. The theoretical framework established here could also inspire new constructions for other aggregate cryptographic primitives under standard assumptions, fostering a new generation of provably secure and scalable blockchain architectures within the next three to five years.

Verdict
This research decisively advances the foundational principles of cryptographic aggregation, delivering a provably secure and highly efficient ordered multi-signature scheme crucial for future scalable and trustless decentralized systems.