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Blind Merged Mining (Consensus layer)

BIP 301. Paul Sztorc.

BIP 301, Blind Merged Mining (Consensus layer). Blind Merged Mining (BMM) allows SHA-256d miners to collect transaction fee revenue from other blockchains, without running any new software (i.e., without "looking" at those alt-chains, hence "blind").

Status in the source: Draft. A reading of the public specification, not a copy of it and not a certification.

Blind Merged Mining (Consensus layer) is worth reading for the rule it actually adds: Blind Merged Mining (BMM) allows SHA-256d miners to collect transaction fee revenue from other blockchains, without running any new software (i.e., without "looking" at those alt-chains, hence "blind").

The five-minute read

The rule

Blind Merged Mining (BMM) allows SHA-256d miners to collect transaction fee revenue from other blockchains, without running any new software (i.e., without "looking" at those alt-chains, hence "blind").

What was already failing

Bitcoin script and block validity only change when a soft fork says an old pattern is now invalid. Without that rule, every node is free to accept what this document wants to reject.

What the number does not mean

The source marks this draft. It is not a live consensus rule just because it has a number.

What a builder should be able to point at

An implementation either constrains BMM, SHA, NMC or it is a different design.

One action, walked through

  1. Open BIP 301 and read the status line before the examples.
  2. Write down the rule in one sentence. A fair version of that sentence is: Blind Merged Mining (BMM) allows SHA-256d miners to collect transaction fee revenue from other blockchains, without running any new software (i.e., without "looking" at those alt-chains, hence "blind").
  3. Name the object that changes: BMM, SHA, NMC.
  4. Ask what an old client, an old contract, or an offline counterparty does. If the document is silent, the silence is part of the design.

The argument, unpacked

What the text is allowed to settle

Bitcoin Improvement Proposal 301 can settle the shape of Blind Merged Mining (Consensus layer). It cannot settle whether a later client, a later fork, or a later wallet still does this.

What this page will not pretend

There is no benchmark, no adoption number, and no claim that the mechanism is safe outside the assumptions written in the source.

What has to be true

  • You are implementing BIP 301 at the status the text itself states: Draft.
  • The object that has to change is BMM, SHA, NMC. A neighbouring document with a similar name is not this one.
  • Activation is a separate mechanism from the opcode or the sighash. This page does not pick a height.

What happened after the paper

The source marks this draft. It is not a live consensus rule just because it has a number. Later documents can narrow, replace, or ignore this one. Cite the number you mean.

What to check before you use the idea

  • Which bytes become invalid under Blind Merged Mining (Consensus layer), and which old transactions stay valid?
  • Is enforcement in consensus, or only in the mempool policy of one client?
  • Which of these objects does the text actually define: BMM, SHA, NMC?

Terms

BIP 301
The public text titled Blind Merged Mining (Consensus layer).
Draft
The document's own label for how finished the text is. It is not a market fact.

The problem the paper names

Bitcoin script and block validity only change when a soft fork says an old pattern is now invalid. Without that rule, every node is free to accept what this document wants to reject.

What the design proposes

  • Blind Merged Mining (BMM) allows SHA-256d miners to collect transaction fee revenue from other blockchains, without running any new software (i.e., without "looking" at those alt-chains, hence "blind").
  • Instead, this block-assembly work is done by alt-chain users.
  • They choose the alt-chain block, and what txns go in it, the fees etc.

How the mechanism is specified

  • Taken from the specification, the next constraint is: Instead, this block-assembly work is done by alt-chain users.
  • Locate BMM, SHA, NMC in BIP 301 and apply it to one transaction or call.
  • Then check the failure the class of rule always has: a node that did not upgrade, a reverted call, a replayed signature, or a peer that does not speak the message.

What this page does not treat as proven

  • A soft fork does not bind a node that never upgrades. It binds the nodes that enforce the new rejection.
  • Activation is a separate mechanism from the opcode or the sighash. This page does not pick a height.
  • The source marks this draft. It is not a live consensus rule just because it has a number.

Why a venture studio still reads it

Use BIP 301 when a pitch says 'Blind Merged Mining (Consensus layer)' without saying whether the rule is consensus, policy, or an interface. The number is the citation. The pitch is not.

This is Blockchain Lab's reading of a public design paper. It is not the paper, not a copy of it, and not an offer of tokens, equity, custody or a partnership. Later network behaviour can diverge from the text. Nothing here is investment, legal or technical advice.

Research status: Design paper. Last reviewed: 1 October 2026. This is a reading of a public paper, not investment, legal or security advice.