Adam Back, the cryptographer and Blockstream chief executive who was namechecked in the original Bitcoin white paper, has thrown his weight behind one of the most debated ideas in Bitcoin development. On 1 October he publicly endorsed covenant opcodes, framing them as a possible last soft fork that could end the cycle of endless protocol upgrades.
The pitch is deliberately counterintuitive. Back wants Bitcoin to stop being upgraded so often, and he believes the way to get there is one more upgrade. Covenant-enabling tools, he argues, would give developers a general purpose toolkit on top of which future innovation could happen without touching the base protocol again.
Two arguments, not one
Back’s case rests on two linked ideas. The first is about stability. A soft fork is a backward compatible change to Bitcoin’s rules, and every one of them is slow, contentious and requires coordination across miners, node operators and developers around the world. Covenant opcodes could absorb much of that future demand for change, meaning the network would need new soft forks far less often.
The second idea is about security. Back has called for formal semantics and mathematical proofs as the foundation for making Bitcoin Script harder to get wrong. Formal semantics means describing exactly what a piece of code does in precise mathematical terms, and the proofs let developers verify that a contract behaves as intended before anyone puts real money behind it.
Covenants in plain English
A covenant is a rule attached to coins that restricts how they can be spent in the future. Today’s Bitcoin Script mostly answers one question, which is whether someone has the right to spend a particular coin. Covenants go further. They would let a script influence where those coins go next, unlocking features like vaults, improved custody setups and more flexible payment channels.
That sounds abstract, but it matters to anyone holding Bitcoin in the UK. Better custody tools and safer scripting directly affect how exchanges and wallet providers protect customer funds.
The two proposals picking up steam
Several concrete covenant proposals have gained renewed attention through 2026. The two most discussed are CTV, formally known as BIP 119, and OP_CAT, designated BIP 347. Both have seen activity through signet testing and draft Bitcoin Improvement Proposals. Signet is a test network where developers can experiment with proposed features without risking any real Bitcoin.
None of these proposals has reached the Bitcoin mainnet. As of early October 2026, CTV and OP_CAT remain in draft or signalling stages, so Back’s endorsement is a statement of direction rather than an imminent change.
The Simplicity connection
Back’s comments also pointed to Simplicity, a smart contract language developed by Blockstream and launched on the Liquid Network in 2025. Liquid is a Bitcoin sidechain operated by Blockstream, and Simplicity was designed with formal verification in mind, which lines up exactly with Back’s emphasis on mathematical proofs for script security.
The alignment is worth noting. The executive advocating for formally verifiable scripting runs the company that built a formally verifiable scripting language. Simplicity’s track record on Liquid may become a live reference point for how base layer covenant proposals are judged.
Modular versus specific, an old argument
Back’s latest remarks are not a sudden conversion. He has consistently promoted modular opcodes over highly specific ones since as early as 2021. The distinction is a core fault line in the covenant debate. Specific opcodes are designed to do one job well and are easier to reason about. Modular opcodes are general purpose tools that can be combined in ways their designers may not have anticipated.
Back has planted his flag firmly in the modular camp. His last soft fork framing is the logical endpoint of that position. Build a general toolkit once, verify it rigorously, and let everything else be built on top.
What should holders watch
For developers, the near term signal is to watch signet activity and the progress of draft BIPs like BIP 119 and BIP 347. Any movement from testing to formal signalling on mainnet would mark a genuine change in momentum. For everyone else, this is protocol level news. Back’s statement carried no immediate market effects and involved no token launches.
Bitcoin changed hands at roughly 84,000 dollars on Thursday, worth around 64,000 pounds in the UK, drifting in a narrow range as traders weighed soft US inflation data against stubbornly high Treasury yields. Crypto assets remain volatile, and UK buyers should remember they are not covered by the Financial Services Compensation Scheme.
Reporting on this story by TradingView News.
