The recent growth of blockchain technology has accelerated research on decentralized platforms. Initial blockchain platforms decide on what should be added to the ledger based on Proof-of-Work (PoW) consensus protocol. PoW requires its participants to perform large computations and leads to massive energy wastage. Recent blockchains aim to replace PoW through Proof-of-Stake (PoS) and Malicious Fault-Tolerant (MFT) consensus protocols. However, the safety of the ledger created by these protocols is at the mercy of the long-term safe-keeping of the private keys of participants. As a result, these blockchains face long-range attacks. To ameliorate this situation, we present the design of our novel Power-of-Collaboration (PoC) protocol, which guards existing PoS and MFT blockchains against long-range attacks. We show that PoC can be easily appended to existing blockchains and only marginally degrades their throughputs.

翻译：区块链技术的近期发展加速了去中心化平台的研究。最初的区块链平台基于工作量证明（PoW）共识协议决定应添加到账本中的内容。PoW要求参与者执行大量计算，导致巨大的能源浪费。最新区块链旨在通过权益证明（PoS）和恶意容错（MFT）共识协议取代PoW。然而，这些协议创建的账本安全性取决于参与者私钥的长期安全保管。因此，这些区块链面临长程攻击。为改善这一状况，我们提出新型协作证明（PoC）协议的设计，该协议可保护现有PoS和MFT区块链免受长程攻击。我们证明，PoC可轻松附加到现有区块链，且仅会略微降低其吞吐量。