The Beginner’s Approach to ThunderCore

Image obtained from ThunderCore´s website.

ThunderCore, in my opinion, is one of the most solid and exciting projects of 2018. They are working on a solution that can be applicable to any blockchain, which consists of the following: a fast path on top of a standard blockchain “the slow chain” where transactions are instantly confirmed, and a slow chain which is used when things go bad. This article explains the project as simple as possible since the target audience is non-technical people.

This is the first of a “Beginner´s approach” article series that will include the most promising projects that in my opinion will be leading the blockchain revolution.

INTRODUCTION

ThunderCore In a Nutshell

Thunder is a secure, high-performance blockchain; which is aiming to enable mass adoption of decentralized applications.

What does ThunderCore have to offer?

• Compatibility: Ethereum smart contracts will be fully supported. You will be able to migrate DApps to Thunder and immediately increase their performance.
• Scalability: process thousands of transactions in a second, nothing is left pending.
• Speed: get your transactions confirmed instantly in less than a second.
• Security: enjoy mathematically grounded security guarantees. Thunder is as secure as existing blockchains but with vastly improved speed and efficiency.

What makes ThunderCore different from a technological standpoint?

Thunder adds a “fast-path” on top of a standard blockchain called the “slow-chain”. In normal conditions, all transactions are instantly confirmed on the fast-path, and barely have to use the slow-chain. If the fast-path is ever disrupted, a provably correct mechanism is invoked to fall back to the slow-chain, and nodes can continue to communicate and confirm transactions on the slow-chain. Once the problems are diagnosed, the fast-path will be revived. Every step of Thunder’s consensus protocol is backed by rigorous mathematical proofs. As a result, Thunder achieves both high throughput and fast confirmation at the rate of thousands of transactions per second.

Why is ThunderCore the simplest, fastest, most expressive and secure blockchain solution?

• Achieves both high throughput and fast confirmation time.
• Provides security and robustness against up to a 50 % attack.
• Directly supports EVM (Ethereum Virtual Machine)-smart contracts and EVM-DApps designed for Ethereum with little or no modifications.
• Comes with a mathematical proof of its security.

Who is behind ThunderCore?

ThunderCore is a team comprised of accomplished entrepreneurs and award-winning scientists and engineers. Not only did they found the Initiative for Cryptocurrency and Contracts (IC3), but they also co-authored the first academic publications on Bitcoin and smart contracts. Further info on the team here.

THE THUNDER PROTOCOL IN A NUTSHELL

Great analogy to explain what ThunderCore is capable to do. Elaine Shi is the ThunderCore´s Chief Scientist.

The Thunder protocol will make use of a simple fast-path protocol in conjunction with an underlying slow-chain to ensure worst-case security under worst-case conditions, and instant-confirmation and high throughput under optimistic conditions. The key idea is to make use of the “fast-path” protocol when things work well, and only use the slow-chain to recover from faults.

THE PROTOCOL AND ITS MAIN FEATURES

What is the principal function of the fast-path?

The fast-path offers both high throughput and instant confirmation of transactions.

What is the principal function of the slow-chain?

The “slow chain” makes sure that no damage can be done to the blockchain, and then to recover in a provably sound manner.

What are the principal actors of the Fast path?

• The Committe: the fast path protocol is executed by a committee of stake-holders.
• The Accelerator: the fast path protocol is coordinated by a central authority called the Accelerator. The Accelerator ’s job is to linearize transactions and data (which is a task that is hard to do in a decentralized way, yet easy for a central authority).

Under what conditions the slow chain has to be used?

• The Accelerator misbehaves or is under attack.
• Less than 3/4 of the Committee are working correctly.
• Network conditions are bad.

How transactions are instantly finalized through the fast-path?

Transactions Flow. Images obtained from here.

S1: the leader proposes transactions with sequence (seq) numbers and sends them to a group of committee players.

S2: members of the committee acknowledge transactions they receive with seq numbers, sign them and send them back to the leader. If committee players receive more than one transaction with the same seq number, they only sign one.

S3: if a transaction has enough acknowledgments, it is viewed as confirmed.

S4: transactions require slightly more than 2/3 acknowledgments to be confirmed.

S5: once conditions are met, the transactions are CONFIRMED.

A more in-depth explanation of how transactions are instantly finalized.

1- All new transactions are sent to the Accelerator.

2- The Accelerator bundles up transactions into micro-blocks, signs each micro-block with increasing sequence numbers seq, and sends out the signed micro-block to a “committee” of players.

3- The committee members acknowledge all Accelerator-signed micro-blocks by signing them, but only acknowledge at most one micro-block per sequence number.

4- When a micro-block has received acknowledgements (i.e., signatures) from more than 3/4 of the committee members, the micro-block is notarized.

5- Participants can directly output their longest sequence of consecutive (in terms of their sequence numbers) notarized micro-blocks — all transactions contained in them are considered confirmed.

How does the fast-path recover from faults?

If a committee member sees some transactions on the slow-chain that have not gotten notarized within a sufficiently long amount of time, they know that the Accelerator (or a large fraction of the committee members) must be cheating or offline. At this point, the committee member will stop signing heartbeat messages. To correct this, the following occurs:

1- As long as just 1/4 of the committee is honest, a cheating Accelerator will be “choked”, so no new heartbeats by Accelerator will be notarized.

2- Everyone that observes the slow-chain will enter the “cool-down” phase and subsequently the slow mode.

3- Once it has entered the slow mode where all transactions are being posted on the slow-chain, the simplest method to reboot the fast path is by posting a “summon” message to the slow-chain to summon committee members to retry at a certain point of time (Thunder nodes can use the slow-chain to discuss and vote on how and when to rebootstrap).

How to select a Committee?

There are many approaches for selecting the committee among the stake-holders:

Method A:

1- Thunder requires anyone who wishes to serve on the committee to put down an escrow on to the slow-chain.

2- Thunder sub-selects a group of 500 members from the entities having put down an escrow on the slow-chain.

3- The selection is performed by an algorithm (method from their earlier work Snow White).

Method B:

Thunder selects the members who have put down the most amount of stake, since we would like to encourage more stake to join the committee and protect the fast path.

The actual algorithm Thunder implemented is motivated by this idea but a carefully crafted variant such that Thunder can prove that the equilibrium behavior satisfies certain desirable properties.

What are the main features of the first Thunder release?

• It will be fully EVM (Ethereum Virtual Machine) compatible to enable direct migration of existing Ethereum DApps.
• Ethereum’s blockchain will be the underlying “slow-chain”.
• Thunder will rely on a single Accelerator; in later versions, the system will be extended to support multiple shards, each having their own dedicated Accelerator.

THUNDERCORE COMPARED TO OTHER BLOCKCHAINS

Refer to the spreadsheet here

CONCLUSION

When it comes to building groundbreaking technology, having an experienced and highly capable team hugely increment the rate of success of any project. ThunderCore has great fundamentals to stand out among existing and new blockchain projects, being an EVM-compatible blockchain gives them an advantage. If Thunder´s team successfully implement all the proposed features and build a strong developers community, the protocol has a tremendous chance of being adopted by new and existing projects built on Ethereum.

The project is still in its early stages, let´s see how things play out for ThunderCore in the coming months.

If you enjoyed this article, please clap it up and share it so that others can find it. Don´t forget to follow me to be the first to know about my upcoming publications.

Acknowledgement: thanks to ThunderCore and Jaime 1700 for the feedback and early draft.

Dukakis Tejada is a Community Moderator, cryptocurrencies enthusiast and investor. He will be writing about the most promising projects that in his opinion will be leading the blockchain revolution; his experience as Community Moderator; and community management related content.

“ The blockchain cannot be described just as a revolution. It is a tsunami-like phenomenon, slowly advancing and gradually enveloping everything along its way by the force of its progression.” — William Mougayar

REFERENCES

• ThunderCore website.
• ThunderCore whipaper.
• DFINITY for beginners.
• DFINITY consensus whitepaper.
• Ethereum whitepaper.
• Making Sense of Ethereum’s Layer 2 Scaling Solutions: State Channels, Plasma, and Truebit.
• Zilliqas´s tech FAQ.
• EOS whitepaper.
• Algorand whitepaper.