Permissioned ledger technologies have gained significant traction over the last few years. For practical reasons, their applications have focused on transforming narrowly scoped use-cases in isolation. This has led to a proliferation of niche, isolated networks that are quickly becoming data and value silos. To increase value across the broader ecosystem, these networks must seamlessly integrate with existing systems and interoperate with one another. A fundamental requirement for enabling crosschain communication is the ability to prove the validity of the internal state of a ledger to an external party. However, due to the closed nature of permissioned ledgers, their internal state is opaque to an external observer. This makes consuming and verifying states from these networks a non-trivial problem.
This paper addresses this fundamental requirement for state sharing across permissioned ledgers. In particular, we address two key problems for external clients: (i) assurances on the validity of state in a permissioned ledger and (ii) the ability to reason about the currency of state. We assume an adversarial model where the members of the committee managing the permissioned ledger can be malicious in the absence of detectability and accountability. We present a formalization of the problem for state sharing and examine its security properties under different adversarial conditions. We propose the design of a protocol that uses a secure public ledger for providing guarantees on safety and the ability to reason about time, with at least one honest member in the committee. We then provide a formal security analysis of our design and a proof of concept implementation based on Hyperledger Fabric demonstrating the effectiveness of the proposed protocol.
BLOWN: A Blockchain Protocol for Single-Hop Wireless Networks under Adversarial SINR
区块链被称为分布式账本技术（DLT），由于其分散性，安全性，不变性和透明度等特性，以及其作为各种应用程序基础设施的潜力，引起了人们的广泛关注。区块链可以为无线网络提供身份管理、数据完整性、访问控制和高级别安全性。然而，以前对区块链无线网络的研究主要集中在提出架构或使用流行的区块链协议构建系统。然而，当在无线网络中采用时，这样的现有协议具有明显的缺点，在无线网络中，节点可能具有有限的物理资源，可能缺少良好建立的可靠信道，或者可能遭受受环境或干扰攻击影响的可变带宽。在本文中，我们提出了一种新的共识协议，名为信道证明（Proof-of-Channel，简称BLOCKCHAIN），利用无线通信的自然属性，并在对抗性SINR模型下为单跳无线网络开发了一种允许的BLOWN协议（BLOCKCHAIN protocol for Wireless Networks）。我们用通用组合框架对BLOWN进行了形式化，并证明了它的安全属性，即持久性和活性，以及它在对抗性干扰，双重支出和Sybil攻击方面的优势，这些也通过广泛的模拟研究得到了证明。
