Bitcoin Proposal BIP-420 Proposes Restoration of OP_CAT Operation Code

Bitcoin Improvement Proposal BIP-420 has officially proposed to restore the OP_CAT opcode, introducing the "Covenants" function to Bitcoin. Udi Wertheimer, co-founder of Taproot Wizards and advocate of OP_CAT, said that OP_CAT will allow for smart contracts, secure cross-chain bridges, on-chain transactions, zero-knowledge proof verification, and other functions to be implemented on Bitcoin. The so-called "Covenants" are an advanced script function that can set specific conditions for the use of Bitcoin in future transactions. This will open up many application scenarios, such as creating secure insurance libraries that allow for transaction rollbacks, automating regular payments, setting up timed transfers for inheritance scenarios, and managing complex financial instruments such as bonds. The proposal was written by Ethan Heilman and Armin Sabouri, and aims to redefine the OP_SUCCESS126 opcode by a soft fork in a backward-compatible manner to restore OP_CAT. However, whether the OP_CAT soft fork can be implemented depends on multiple considerations such as technology, security, and community consensus. The concept of "Covenants" in Bitcoin can be traced back to at least 2013. In addition to OP_CAT, there are multiple "Covenants" proposals such as CTV, CSFS, and LNHANCE, which are currently in different stages of research and discussion.