Stacks
Overview
Status
Mainnet
Type
Anchor Chain
Fee Token
STX
BTC Supply
₿0
Stacks is a sidechain that aims to be programmability layer for Bitcoin. It uses a novel execution environment, Clarity. Stacks uses a hybrid PoS mechanism (PoX) and derives economic security from its native token (STX).
CUSTODY
DATA AVAILABILITY
OPERATORS
FINALITY ASSURANCE
Trust Assumption Review
BTC Custody
Very High
🛑
sBTC
sBTC is managed by a federation of 14 institutional signers. Withdrawals are not live
sBTC is a bridge between bitcoin and stacks managed by 14 institutional signers. sBTC on Stacks is backed by BTC held in a wallet managed by these signers. The identities of entities participating in the sBTC bridge are publicly known.
If 10 of the signers colluded, they could steal all of the BTC backing sBTC. You can find the signers here.
While managed by a public federation, sBTC receives a Very High score as withdrawals are not currently live.
If 10 of the signers colluded, they could steal all of the BTC backing sBTC. You can find the signers here.
While managed by a public federation, sBTC receives a Very High score as withdrawals are not currently live.
Data Availability
Medium
⚠️
Data availability requirement is fulfilled through Stacks' full nodes
Stacks posts state roots to Bitcoin, but not full transaction calldata. Because of this, Stacks' state cannot be reconstructed using only data from Bitcoin. Stacks has a permissionless validator and node operator set which participate in making data availability readily available.
Network Operators
Medium
⚠️
Leverages a permissionless consensus mechanism
Stacks has a permissionless block production mechanism, Users must trust Stacks validators to include their transactions in blocks. Anyone with sufficient capital and resources can participate as a Stacks miner.
Finality Guarantees
Under Review
🔬
State transitions validated and finalized by Stackers. We are reviewing if the mechanism inherits finality guarantees from bitcoin
The Nakamoto upgrade sees Stacks checkpoint its state to bitcoin. We are reviewing the details around Stacks' reorg resistance guarantees from bitcoin.
See the technology section for a description on Nakamoto consensus.
See the technology section for a description on Nakamoto consensus.
Bitcoin Security
Unilateral exits to Bitcoin not possible
Users cannot unilaterally exit from the Stacks sidechain with an L1 Bitcoin transaction. They currently trust centralized operators to process their withdrawals.
The protocol does not enable MEV on Bitcoin, but Bitcoin miners can extract MEV from Stacks
Stacks' mining process requires a Bitcoin miner to submit a block commit as a bid to build a Stacks block. It is possible for a Bitcoin miner to censor all bids to build Stacks' blocks when building a Bitcoin block. Since the active Bitcoin miner would be the only entity with the ability to win a Stacks block, they could submit a minimal amount of funds to win the block and receive all STX rewards. This MEV-extraction scenario looks to be solved in the Nakamoto upgrade.
🔬We are reviewing this section of the assessment.
🔬We are reviewing this section of the assessment.
An alternative token plays a role in network security
The STX token is required to pay for transaction fees and smart contract execution on the Stacks network. It is also used as a reward for miners who participate in the PoX consensus mechanism. The token is indirectly required for the security of the network, as block production by miners is incentivized by STX.
Stacks indirectly contributes to the security budget
Stacks sees Bitcoin miners bid on the opportunity to win Stacks blocks and earn fees for doing so. However, miners rewards are paid out in STX tokens via a distinct mining set up.
Withdrawals
Users trust centralized operators to process their withdrawals
Stacks users deposit BTC into Stacks through custodial bridge mechanisms. They trust that the operators of these bridges (e.g. aBTC and xBTC) will not steal their Bitcoin assets, or censor their withdrawals.
Technology
Clarity
Stacks leverages the Clarity execution environment. The Clarity language is a subset of Lisp, and is not Turing-complete as a design choice. However, it is still expressive enough to build complex smart contracts and replicate much of the functionalities from Turing-complete environments like the EVM (i.e., DeFi, NFTs, etc.). Stacks is able to read Bitcoin state, due to both Clarity and its integrated PoX consensus mechanism. This allows for events on Stacks to be triggered by Bitcoin activity, or for smart contracts to read Bitcoin state during their execution.
Proof-of-Transfer
Proof-of-Transfer (PoX) is Stacks' consensus mechanism, based on Proof-of-Burn. PoX involves Bitcoin miners bidding BTC for the right to mint a Stacks block. The winning miner creates the block, and is rewarded with the STX block reward and STX transaction fees from the block. The miner's bid is paid to STX stackers (stakers). This system allows for STX stackers to earn native BTC yield, and creates an additional revenue stream for miners, similar to merge-mining.
Nakamoto
In Nakamoto Consensus, miners commit to mining Stacks blocks by broadcasting commit transactions on the Bitcoin blockchain. After winning the right to produce Stacks blocks, the selected miner gains the exclusive right to build and append Stacks blocks for a specific tenure, typically lasting about 10 minutes, corresponding to Bitcoin's block time. These blocks are then validated by Stackers, participants in a Proof-of-Stake-like mechanism. Once validated, blocks are finalized and added to the Stacks blockchain.,
Use Cases
Onchain applications
The most popular use case for Stacks is onchain applications. Stacks has a number of applications, including lending, borrowing, and decentralized exchanges.
Source Code
Code is open-source
All code related to the Stacks project is free and open source.
Knowledge Bits
Learn more