OP_CAT recently unveiled its BIP-420 proposal amid the ongoing debate surrounding covenants within the Bitcoin community.
According to Udi Wertheimer at However, it is worth noting that the proposal has not yet received official status as a Bitcoin Improvement Proposal (BIP).
Covenants on Bitcoin (BTC) are essentially advanced script functions that dictate specific terms on how bitcoins can be spent in future transactions.
Covenants have the potential for a variety of use cases, from creating secure vaults that enable reversible transactions to enabling automated recurring payments, time-sensitive transfers for inheritance purposes and even complex financial instruments such as escrows and bonds.
Originally, OP_CAT was part of Bitcoin’s early opcodes, but was disabled by Satoshi Nakamoto in 2010 due to concerns about potential vulnerabilities. An opcode, a command within the Bitcoin scripting language, is crucial when performing operations within Bitcoin scripts.
https://twitter.com/udiwertheimer/status/1782503906142019874?p=10
The proposalled by Ethan Heilman and Armin Sabouri, proposes to reintroduce OP_CAT via a backward-compatible soft fork, specifically by redefining the opcode OP_SUCCESS126, which aims to reduce confusion by preserving the original opcode value.
Its proponents claim that reintroducing OP_CAT would expand Bitcoin’s capabilities, simplify decentralized protocols, support advanced multi-sig setups, and increase Bitcoin’s scripting power and flexibility.
However, realizing an OP_CAT soft fork depends on technical feasibility, security considerations and reaching community consensus.
In addition to OP_CAT, several other covenant proposals are being considered within the Bitcoin ecosystem, each with its unique approach and potential tradeoffs. These include Check Template Verify (CTV), OP_CHECKSIGFROMSTACK (CSFS) and LNHANCE, each offering different functionalities and levels of formalization in their proposals.
