Smart Bitcoin Cash

Basics

• Based in:
• Started in / Announced on: Q2-2020 / 29-4-2021
• Testnet release: 29-4-2021
• Mainnet release:
• From their website (-5-2021):

"Smart Bitcoin Cash (smartBCH for short) is a sidechain for Bitcoin Cash and has an aim to explore new ideas and unlock possibilities. It is compatible with Ethereum's EVM and Web3 API and provides high throughput for DApps in a fast, secure, and decentralized manner."

Token

Launch

• From the whitepaper (4-2021):

"Smart Bitcoin Cash will not introduce new tokens. Its native token is BCH, and its gas fees are paid in BCH."

Utility

• From their website (3-5-2021):

"Earn extra reward for Bitcoin Cash's miners and holders, who can elect Smart Bitcoin Cash's validators with hash power and locked coins, respectively."

• From the whitepaper (4-2021):

At the end of a quorum‘s tenure, half of the collected gas fees will be rewarded to the validators and the other half will be burned. In this sense, BCH will become a deflationary currency. A validator must pledge enough collateral to get its gas fee reward, and the reward must undergo a lock period before it can be spent.

Technology

• Whitepaper can be found here (4-2021).
• Code can be viewed here.

Implementations

• Built on: Tendermint consensus (4-2020).
• Programming language used: "It can use any language which compiles to EVM bytecode." (30-4-2021).
• From their website (3-5-2021):

"Has been developed from scratch and is made of several low-level libraries which fully leverage the potential of hardware, especially its inherent parallelism."

Transaction Details

• Capacity (TPS).
• From their FAQ (30-4-2021):

"Limited tests currently show that the underlying storage engine can support more than 600 times the throughput of Ethereum. However, there are still many factors to consider when running the whole chain, and there will be some challenges we might face. We hope that within 20 months, the throughput per second will be 100 times larger than ETH1.0. When smartBCH initially launches, we estimate a throughput 10-20 times larger than ETH1.0."

• From Bitcoin.com (2-5-2021) with an interview with the lead dev:

"First we abandoned the single-thread semantics defined in Ethereum’s yellow paper. Single-thread semantics is not a must to support EVM and Web3 and it blocks many optimizations. Second, we developed a lot of low-level libraries which support parallel execution of EVM transactions to exploit the potential of modern CPU and SSD. Last but not least, we optimized the EVM execution engine and storage engine, which makes each EVM instruction run faster."

• Latency:
• SmartBCH, like Ethereum, uses an account model instead of a UTXO model.

How it works

• From their website (3-5-2021):

1. "MoeingADS uses a single-layer architecture, accessing the file system directly without having to use any other databases. It is a KV database that can provide existence and non-existence proof. It can replace Ethereum's MPT as an authenticated data structure.
2. MoeingEVM is a parallelized execution engine that currently manages multiple EVM contexts and executes multiple transactions. It allows transactions from several blocks to be mixed and reordered, such that independent transactions can run in parallel to maximize throughput.
3. MoeingDB is an application-specific database that stores blockchain history, and developed with blockchain's characteristics in mind, enabling it to suit blockchain's workload best. Based on its features, an open-source high QPS Web3 API can be built.
4. MoeingKV is a KV storage much faster than LevelDB in reading and writing, at the cost of removing iteration support. In underlying data structure design and code implementation, MoeingKV produces trade-offs and optimizations to speed up normal read and write operations.
5. MoeingAOT is an ahead-of-time compiler for EVM. MoeingAOT can compile frequently used EVM bytecode into native code, which would consequently be saved as a dynamically linked library. Executing the native code would be orders of magnitude faster than interpretation."

• From their FAQ (30-4-2021):

"Unlike Ethereum, smartBCH reorders transactions in a pseudorandom way to mitigate the problem of front-running, which makes it much harder for a validator to enforce its preferred transaction order. Besides, smartBCH also reorders transactions to maximize parallelism."

Staking

• From the whitepaper (4-2021):

"The quorum of validators are elected by both hash power and BCH owners, and they take on duties in epochs.

An epoch contains 2,016 blocks (takes about two weeks). During an epoch, BCH owners prove their ownerships of time-locked UTXOs and use the values of these UTXO to vote for a validator; whereas mining pools use coinbase transactions to vote. This is a hybrid consensus model: proof of hash power and stakes. The voting process is performed on Bitcoin Cash's mainnet and totally permissionless because a new validator only needs endorsements from miners and/or holders.

An epoch's end time is the largest timestamp of its blocks, and its duration time is the difference between the end times of adjacent epochs. The quorum elected during an epoch will stay in a stand-by state for about 5% of the epoch's duration time. Then it takes its turn to be on duty, until the next quorum leaves its stand-by state, which is necessary because any Bitcoin Cash reorganization may alter the blocks in an epoch.

Each validator must pledge some BCH as collateral, which would be slashed should it misbehaves during its duty. At the first phase after Smart Bitcoin Cash's launch, only hash power is used for electing validators. Locking BCH at mainnet for staking will be implemented later and take effect in a future hard fork."

Interoperability

• From the whitepaper (4-2021):

"To bootstrap Smart Bitcoin Cash, we are inviting the major players in Bitcoin Cash's ecosystem to run a federated two-way pegged gateway, which bridges the mainnet and Smart Bitcoin Cash to transfer BCH bidirectionally, just like how RSK and Liquid work. These players are not necessarily validators.

We are aware that Bitcoin Cash's scripting language is capable of implementing a non-custodial trustless gateway by using a lock script to trace the voting process carried out inside coinbase transactions. However, this scheme has not been field-proven. We will write up dedicated proposals to describe this scheme and it will be implemented in CashScript upon passing. Afterwards, Smart Bitcoin Cash will switch to this new scheme in a hard fork."

• From their FAQ (30-4-2021):

"Currently smartBCH does not directly interoperate with Ethereum, but in time a gateway may bridge assets between them. In the future, bridges based on smart contracts are also possible, with a scheme similar to rainbow bridge."

Roadmap

• Can be found [Insert link here].
• From the whitepaper (4-2021):

"MoeingADS, MoeingEVM and MoeingDB are almost finished. Regardless, some throughput tests are necessary before Smart Bitcoin Cash can be officially launched.

MoeingAOT will be ready and take effect after a hard fork by the end of 2021. MoeingKV will also be developed in 2021 with the hope to meet potential demands from Bitcoin Cash's mainnet.

MoeingRollup and MoeingLink will be developed in 2022. By then, if the traffic of Smart Bitcoin Cash is congested, they will be deployed in a hard fork for further scaling."

Audits

• Bug bounty program can be found here but details are not given (3-5-2021).

Usage

Projects that use or built on it

• From Bitcoin.com (2-5-2021) with an interview with the lead dev:

"We will have several companies confirmed and will join our testnet and participate to be the validator. And we have several new applications developed and dedicated for Smartbch and several existing applications being ported to Smartbch."

Pros and Cons

Cons

• Starts out with a federated bridge between Bitcoin Cash and SmartBCH (4-2021).

Team, Funding, Partnerships, etc.

Team

• Full team can be found [here].
• Wang Kui; lead dev