有趣的共识算法Braided PoW

Kadena通过区块链编织（链网）“braid” of chains 解决区块链扩展性难题，同时通过互相验证其他链的区块头来增强系统安全性，是一个解决区块链三角难题比较具有创新的项目。

Kadena有两位创始人：

Will Martino：耶鲁大学毕业、JP Morgan区块链首席工程师、SEC首席科学顾问

Stuart Popejoy：加州大学伯克利分校毕业、JP Morgan区块链小组设计开发人员

Kadena具有以下特点：

1.高吞吐量：私有链8000 tps，公有链10000 tps

2.形式化验证的代码安全

3.友好的编程语言Pact

下面是Kadena共识算法Braided PoW的介绍

Kadena is the only system I’m aware of that’s attempting to solve the scalability trilemma using a PoW scheme. Kadena accomplishes this by creating a “braid” of chains that it calls Chainweb. In Chainweb, each chain must, in addition to validating transactions in its own chain, validate block headers of some number of pre-specified chains in order to produce a new block.

To relay messages and value across chains, users need to submit Merkle proofs asserting the state of one chain to other chains in the Chainweb. Because not all chains are directly connected, users may have to “hop” a few times to relay a message from one chain to another.

At first glance, this looks like Ethereum’s proposal for sharding (more on that below). However, whereas Ethereum’s sharding implementation separates transaction collation and validation into spoke chains and a single hub chain respectively, Kadena doesn’t unbundle transaction verification and consensus. In Chainweb, every chain maintains its own consensus. Kadena presents a fundamentally unique approach.

Kadenavisualizes ChainWeb as follows:

One of unique traits of ChainWeb is that scaling the system explicitly

increasessecurity. Why? Because it becomes harder to mount 51% attacks across an increasing number of chains, each of which references blocks from every other chain. In this model, undoing a transaction on one chain requires undoing transactions on every other chain in the system. Given how naturally intertwined the chains are, this becomes exponentially more difficult as the number of chains grows. This stands in contrast to blockchains on leg 3 of the triangle, in which the safety of the system in aggregate doesn’t substantially increase as the number of chains grows.

This design basically solves the scalability trilemma. But there is one major trade off: TTF and cross-chain latency.

Individual chains could be many hops from one another. Kadena aims to offer

Despite this limitation, Kadena presents a real solution to solving the scalability trilemma that’s built on aprovenconsensus model: PoW. Although braiding adds a new dynamics to the system as a whole, each chain is a PoW chain. PoW has undergone much more scrutiny than proof-of-stake (PoS). It takes years to demonstrate the safety of a consensus scheme in the real world. Because of this, there is real value and opportunity for Kadena in building a scalable system on PoW consensus.

On the triangle, Kadena falls here:

Kadena官网：

http://kadena.io/index.html