@inproceedings{12167,
  abstract     = {Payment channels effectively move the transaction load off-chain thereby successfully addressing the inherent scalability problem most cryptocurrencies face. A major drawback of payment channels is the need to “top up” funds on-chain when a channel is depleted. Rebalancing was proposed to alleviate this issue, where parties with depleting channels move their funds along a cycle to replenish their channels off-chain. Protocols for rebalancing so far either introduce local solutions or compromise privacy.
In this work, we present an opt-in rebalancing protocol that is both private and globally optimal, meaning our protocol maximizes the total amount of rebalanced funds. We study rebalancing from the framework of linear programming. To obtain full privacy guarantees, we leverage multi-party computation in solving the linear program, which is executed by selected participants to maintain efficiency. Finally, we efficiently decompose the rebalancing solution into incentive-compatible cycles which conserve user balances when executed atomically.},
  author       = {Avarikioti, Georgia and Pietrzak, Krzysztof Z and Salem, Iosif and Schmid, Stefan and Tiwari, Samarth and Yeo, Michelle X},
  booktitle    = {Financial Cryptography and Data Security},
  isbn         = {9783031182822},
  issn         = {1611-3349},
  location     = {Grenada},
  pages        = {358--373},
  publisher    = {Springer Nature},
  title        = {{Hide & Seek: Privacy-preserving rebalancing on payment channel networks}},
  doi          = {10.1007/978-3-031-18283-9_17},
  volume       = {13411},
  year         = {2022},
}

@inproceedings{12168,
  abstract     = {Advances in blockchains have influenced the State-Machine-Replication (SMR) world and many state-of-the-art blockchain-SMR solutions are based on two pillars: Chaining and Leader-rotation. A predetermined round-robin mechanism used for Leader-rotation, however, has an undesirable behavior: crashed parties become designated leaders infinitely often, slowing down overall system performance. In this paper, we provide a new Leader-Aware SMR framework that, among other desirable properties, formalizes a Leader-utilization requirement that bounds the number of rounds whose leaders are faulty in crash-only executions.
We introduce Carousel, a novel, reputation-based Leader-rotation solution to achieve Leader-Aware SMR. The challenge in adaptive Leader-rotation is that it cannot rely on consensus to determine a leader, since consensus itself needs a leader. Carousel uses the available on-chain information to determine a leader locally and achieves Liveness despite this difficulty. A HotStuff implementation fitted with Carousel demonstrates drastic performance improvements: it increases throughput over 2x in faultless settings and provided a 20x throughput increase and 5x latency reduction in the presence of faults.},
  author       = {Cohen, Shir and Gelashvili, Rati and Kokoris Kogias, Eleftherios and Li, Zekun and Malkhi, Dahlia and Sonnino, Alberto and Spiegelman, Alexander},
  booktitle    = {International Conference on Financial Cryptography and Data Security},
  isbn         = {9783031182822},
  issn         = {1611-3349},
  location     = {Grenada},
  pages        = {279--295},
  publisher    = {Springer Nature},
  title        = {{Be aware of your leaders}},
  doi          = {10.1007/978-3-031-18283-9_13},
  volume       = {13411},
  year         = {2022},
}

@inproceedings{12298,
  abstract     = {Existing committee-based Byzantine state machine replication (SMR) protocols, typically deployed in production blockchains, face a clear trade-off: (1) they either achieve linear communication cost in the steady state, but sacrifice liveness during periods of asynchrony, or (2) they are robust (progress with probability one) but pay quadratic communication cost. We believe this trade-off is unwarranted since existing linear protocols still have asymptotic quadratic cost in the worst case. We design Ditto, a Byzantine SMR protocol that enjoys the best of both worlds: optimal communication on and off the steady state (linear and quadratic, respectively) and progress guarantee under asynchrony and DDoS attacks. We achieve this by replacing the view-synchronization of partially synchronous protocols with an asynchronous fallback mechanism at no extra asymptotic cost. Specifically, we start from HotStuff, a state-of-the-art linear protocol, and gradually build Ditto. As a separate contribution and an intermediate step, we design a 2-chain version of HotStuff, Jolteon, which leverages a quadratic view-change mechanism to reduce the latency of the standard 3-chain HotStuff. We implement and experimentally evaluate all our systems to prove that breaking the robustness-efficiency trade-off is in the realm of practicality.},
  author       = {Gelashvili, Rati and Kokoris Kogias, Eleftherios and Sonnino, Alberto and Spiegelman, Alexander and Xiang, Zhuolun},
  booktitle    = {Financial Cryptography and Data Security},
  isbn         = {9783031182822},
  issn         = {1611-3349},
  location     = {Radisson Grenada Beach Resort, Grenada},
  pages        = {296--315},
  publisher    = {Springer Nature},
  title        = {{Jolteon and ditto: Network-adaptive efficient consensus with asynchronous fallback}},
  doi          = {10.1007/978-3-031-18283-9_14},
  volume       = {13411},
  year         = {2022},
}