A Collection of Resources Related to Covenants
"Covenants are a category of proposed changes to Bitcoin’s consensus rules that would allow a script to prevent an authorized spender from spending to certain other scripts."
- The following is a collection of resources related to covenants, aggregated and maintained by Robin Linus from ZeroSync. Follow his repository for the latest version of the collection.
A collection of resources related to covenants
A collection of resources related to covenants. GitHub Gist: instantly share code, notes, and snippets.
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Covenant-enabling Bitcoin Features
- BIP119: CHECKTEMPLATEVERIFY (CTV) by Jeremy Rubin
- BIP118: SIGHASH_ANYPREVOUT (APO) (aka SIGHASH_NOINPUT) by Christian Decker and Anthony Towns
- OP_CAT by Andrew Poelstra
- OP_CHECKSIGFROMSTACK (CSFS) + OP_CAT
- OP_TAPLEAF_UPDATE_VERIFY (TLUV) by Anthony Towns
- TXHASH + CHECKSIGFROMSTACKVERIFY (TXHASH + CSFS) by Russel O'Connor
- OP_EVICT by ZmnSCPxj
Properties of Covenants
- Granularity: Which transaction fields can be defined by the covenant?
- Overhead: How many bytes are required per TX?
- Simplicity: How complex is the implementation and the usability?
- Status: Is there a BIP? PR? Reviews? Signet? Testnet? Signals? Merged?
- Recursion: Can the covenant be applied endlessly to itself?
- Use cases: For which applications is the covenant the optimal solution?
Resources
- CTV Website
- APO Website
- bitcoinops.org - Covenants
- bitcoinops.org - Covenant opcode proposal
- Bitcoin Covenants (Möser et al, 2016)
- Enhancing Bitcoin Transactions with Covenants (O'Connor et al, 2017)
- Bitcoin Covenants: Three Ways to Control the Future (Swambo et al, 2020)
- bitcoincovenants.com - A compilation of research on Bitcoin Covenants
- Jeremy Rubin AMA
- UnhashedPodcast - Russell O’Connor’s reframing of OPs APO+CTV
- CoinCovenants using SCIP signatures, an amusingly bad idea. (2013)
- Covenants in Elements Alpha (2016)
- Bitcoin2022 - What Are Covenants? (Video)
- Eltoo with Anyprevout and Taproot
- CTV Telegram Group
- How to emulate SIGHASH_NOINPUT using CHECKSIGFROMSTACKVERIFY?
Comparisons to CTV
- Anthony Towns: "I don't think of TLUV as an alternative to CTV"
- Christian Decker: "I consider the two proposals [APO and CTV] complementary, and not competing"
- Alternatives to CTV
Projects based on covenants
- CTV use cases
- Simple CTV Vault
- Spacechains
- Stakechains
- CTV dramatically improves DLCs
- Automated Market Maker by Bitmatrix
CTV Activation - Pros and Cons
Pros
- "Covenants have been discussed for more than 6 years."
- "There is strong consensus that Bitcoin should support covenants."
- "CTV is the most conservative approach to enable covenants."
- "The BIP was finalized over two years ago."
- "The code is well tested and reviewed."
- "People are testing vaults and other covenants live on the CTV signet."
- "There are no objections against CTV on the code level."
- "For 5 months there has been a 5.5 BTC bug bounty program funded by community members."
- "Many community members support the activation of CTV."
Cons
- "The strongest technical argument against bip119 is: since we have to do some soft fork for covenants let’s activate full-featured covenants right away instead of causing multiple forks with overlapping features."
- "The most likely alternative seems to be TXHASH + CSFS. It combines Eltoo fans with ctv fans in a way that makes technical sense, it satisfies those who want more complex covenants going forward, the conversational well around it is less poisoned. The main downside is that it uses a few more bytes. The work that needs to be done to get it in safely can be overcome with effort."
- "However, nobody is working on it. There's no BIP yet. No review. Not even remotely a PR."
- "The number of bitfields in TXHASH is high, so the limiting factor would be writing a large number of both tests and arguing that any possible permutation of those bitfields does not lead to some resource exhaustion attack on some inputs."
- "It would take years to activate it."
