Stacks Improvement Proposals.

Non-fungible tokens - NFTs for short - are digital assets registered on blockchain with unique identifiers and properties that distinguish them from each other. SIP-009 defines the trait for how ownership of an NFT is managed. Fungible tokens - FTs for short - are digital assets where each token can be replaced by another token (see SIP-010). Semi-fungible tokens are digital assets where each token has a unique identifier and is dividable into fungible parts (see SIP-013). This SIP aims to provide a flexible standard to attach metadata to NFTs, like descriptions or urls to digital files. The s…

The Signed Structured Data specification describes a standard way to deterministically encode and sign Structured Data. Structured Data is data that can be represented in human-readable format and used in applications and smart contracts. The aim of the standard is to produce signatures that are straightforward and inexpensive to verify by smart contracts.

As the use of tokens (fungible and non-fungible) has grown in popularity, Stacks developers have found novel ways to define and use metadata to describe them. This rich data is commonly cached and indexed for future use in applications such as marketplaces, statistics aggregators, and developer tools like the Stacks Blockchain API. Occasionally, however, this metadata needs to change for a number of reasons: artwork reveals, media storage migrations, branding updates, etc. As of today, these changes do not have a standardized way of being propagated through the network for indexers to refresh…

This SIP adds bitwise operations to the Clarity language which could simplify the implementation of smart contracts that require manipulation of bits. The changes include the addition of the following operations: - Bitwise Xor (bit-xor) - Bitwise And (bit-and) - Bitwise Or (bit-or) - Bitwise Not (bit-not) - Binary Left Shift (bit-shift-left) - Binary Right Shift (bit-shift-right)

This document describes a consensus-breaking change to the Stacks blockchain that would enable faster and more reliable Stacks blocks. In this proposal, Stacks block production would no longer be tied to miner elections. Instead, miners produce blocks at a fixed cadence, and the set of PoX Stackers rely on the miner elections to determine when the current miner should stop producing blocks and a new miner should start. This blockchain will only fork if 70% of Stackers approve the fork, and chain reorganization will be as difficult as reorganizing Bitcoin. This proposal, dubbed the "Nakamoto" r…

On 19 April 2023, it was discovered that there was a bug in the PoX smart contract which would allow a user to claim that they have stacked far, far more STX than they had locked. Exploiting this bug both allows the user to increase their PoX reward slot allotment, while also driving up the stacking minimum. Furthermore, it creates the conditions for a network-wide crash: if the total amount of STX stacked as reported by the PoX smart contract were to ever exceed the total amount of liquid STX, then the node would crash into an irrecoverable state. This bug has already been triggered in the wi…

On 1 May 2023, it was discovered that smart contracts deployed prior to Stacks 2.1 that exposed public methods with trait arguments could not be invoked with previously working trait-implementing contract arguments. This bug was caused by the activation of Stacks Epoch 2.2 (https://github.com/stacksgov/sips/blob/main/sips/sip-022/sip-022-emergency-pox-fix.md). This SIP proposes an immediate consensus-breaking change to introduce a new Stacks epoch 2.3 that corrects this regression. This SIP proposes a Bitcoin activation height of 788,240

On 8 May 2023, a critical Denial-of-Service vulnerability manifested in the Stacks network. While the initial DoS threat was remedied through a non-consensus breaking hotfix, the underlying bug that triggered the vulnerability requires consensus changes to fix. This underlying bug has existed in the Stacks blockchain implementation since the launch of Stacks 2.0, and has the potential to impact the functionality of contracts even if they do not currently rely on the buggy behavior. This SIP proposes a consensus-breaking change to be included in the SIP-022 hardfork (Epoch 2.4) to remediate thi…

SIP-021 defines a threshold signature scheme called Weighted Schnorr Threshold Signatures (WSTS), a Schnorr signature scheme based on FROST whereby a set of mutually-distrustful parties produce a single Schnorr signature from shares of a private key. No party knows the private key; a signature can only be produced if a threshold of parties agree to produce a signature. WSTS is used in SIP-021 to provide a means for Stackers to collectively append blocks to the Stacks blockchain in a way that achieves Bitcoin finality for Stacks. Because a block can only be attached if a large fraction of the s…

This SIP proposes a new multisig transaction format which is intended to be easier to use than the current format described in SIP-005. It does not remove support for the current format, rather it is intended to co-exist with the old format and give users a choice of which format to use. The issue with the current format is that it establishes a signer order when funds are sent to multisig account address, and requires signers to sign in the same order to spend the funds. In practice, the current format has proven difficult to understand and implement, as evidenced by the lack of Stacks multis…

This SIP proposes a new wrapped Bitcoin asset, called sBTC, which would be implemented on Stacks as a SIP-010 token. sBTC enables seamless and secure integration of Bitcoin into the Stacks ecosystem, unlocking decentralized applications and expanding Bitcoin's utility through smart contracts. Stacks today offers a smart contract runtime for Stacks-hosted assets, and the forthcoming Stacks 3.0 release provides lower transaction latency than Bitcoin for Stacks transactions. By providing a robust BTC-wrapping mechanism based on threshold signatures, users would be able to lock their real BTC on t…

The first Stacks halving is expected to take place 210,384 Bitcoin blocks after the Stacks 2.0 starting height, 666,050, which is Bitcoin height 876,434, which is set to occur during Reward Cycle 100 in December 2024, cutting the STX block reward from 1,000 STX to 500 STX. This SIP proposes a modification to the emissions schedule given that the network is going through two major launches (Nakamoto and sBTC) which rely on predictable economic incentives. The proposed schedule modification and associated STX emission rate would create time for Nakamoto and sBTC to launch and settle in, but, bei…

This SIP proposes common RPC methods to use for the Stacks blockchain's "Connect" and "Auth" systems. The goal is to replace the current Connect interface, primarily used by web applications to connect with browser extensions and mobile apps with a more straightforward protocol. This proposal's goal is to standardize JSON compatible interfaces for use with wallet interfaces.

Stacks' goal as an ecosystem is to empower the creation of the Bitcoin economy - we envision that all projects that want to build on Bitcoin, from DeFi to gaming, memecoins to NFTs, and marketplaces to identity, should be built on top of Stacks. Stacks is transitioning from a tech-first to a traction-first phase, fueled by a new endowment and streamlined operations. The proposal raises fresh capital to put Stacks on par with other top projects, addressing historic underfunding and unlocking the ability to compete at scale. A new operational entity will scale execution, while a community-govern…

This SIP proposes a change to the stacking process so that Stackers can change their stacking settings without the so-called cooldown cycle. Furthermore, the relationship between Stackers and signers is strengthened and stacking overall is simplified. The specification defines that - solo Stackers and delegating Stackers have to follow the same flow and use the same contract functions: All users delegate block voting power to signers. - Stackers can change their stacking settings for the next cycle before the prepare phase, including the chosen signer (switch pools). - locked Stacks tokens are…