RoadmapsProjects
Sign in./start

Learn

RoadmapsProjects

Contribute

DiscoverIssues

Account

Sign in./start-building

Become an Open Source Builder. Learn. Build. Contribute.

Learn

RoadmapsProjectsStart Building

Contribute

DiscoverIssues

Account

Sign inDashboardSettings

Legal

PrivacyTerms

© 2026 Pull // all rights reserved

PrivacyTerms

lesson // bitcoin

Multisig & Timelocks

Shared custody, CHECKMULTISIG, CSV, CLTV, and MuSig patterns.

intermediate5 days

Public lesson — sign in to track progress on this roadmap.

./sign-in

On this page

Learning objectives

  • Explain m-of-n multisig custody models
  • Use CLTV and CSV mental models correctly
  • Contrast on-chain multisig with aggregated MuSig/Taproot approaches

study // plan

Lessons are primers. Depth comes from required reading, interactive labs, reflection, and a hands-on check with evidence — the BOSS study pattern.

Research on Bitcoin Search
multisigBIP67

Required reading

  • bookMastering Bitcoin

    Ch. 7: Authorization and Authentication

Reflection prompts

  1. Explain Multisig & Timelocks to a teammate without jargon — what problem does it solve?
  2. What would break in production if you misunderstood Multisig & Timelocks?
  3. Which BIP, book chapter, or Core doc is authoritative here, and what did you verify?

Lab // Regtest check

After reading, run one hands-on check related to Multisig & Timelocks. Prefer local regtest or Polar over mainnet.

evidence required

  • ·Command output or screenshot from your local lab
  • ·One sentence on what you observed vs expected
  • ·Link to the required reading section you used

Multisig means multiple keys must cooperate to spend. Timelocks add “not before” constraints. Together they power vaults, inheritance designs, and Lightning’s security model.

Why this matters

Shared custody without multisig is usually a single point of failure. Lightning’s justice system depends on relative timelocks. Builders who blur absolute vs relative time create unsafe contracts.

Analogy

Multisig is a safe deposit box needing two keys. A timelock is a time-delay lock that refuses to open until a date, or until enough time has passed since the box was last sealed.

Multisig patterns

Classic Script uses OP_CHECKMULTISIG for on-chain m-of-n. Modern approaches often prefer Taproot + MuSig2 so cooperative spends look like single-sig.

Policy example: 2-of-3 keys OR (1 key after 90 days)

Loading diagram…

Policies combine thresholds and time for safety and recovery.

Absolute vs relative timelocks

further reading

  • bipBIP-65 CLTV
  • bipBIP-68 Relative lock-time
  • bipBIP-112 CSV

progress // sign in

Reading is public. Sign in to mark lessons complete, sync across devices, and unlock your roadmap.

./sign-in-to-track
prevTaproot & TapscriptnextMempool & Fees

On this page

Press Shift + ? for keyboard shortcuts.

Press R to research on Bitcoin Search.

  • CLTV (BIP-65): absolute, unlock after a block height or timestamp
  • CSV (BIP-112 / BIP-68): relative, unlock after the output has confirmed for a relative period

Lightning commitments lean on CSV so old states become punishable after delays.

Wall clocks are not consensus

Nodes use block-based rules. Designing “7 days” means encoding that delay in locktime semantics, not trusting a server clock alone.

Common mistakes

  • Building 2-of-3 without tested recovery paths and key ceremonies
  • Using absolute locks where relative locks were required (and vice versa)
  • Forgetting that mempool policy may delay non-standard scripts

Worked mental model

Re-read the diagrams in this lesson once out loud in plain language. If you cannot explain the flow to a friend without jargon, pause and revisit Mastering Bitcoin / Mastering Lightning chapters linked in Resources. Chapter references are intentional, not decorative.

Hands-on habit

Every protocol idea should be paired with one local experiment:

  1. Reproduce the happy path on regtest (or Polar for Lightning)
  2. Break it on purpose (wrong fee, expired invoice, offline peer)
  3. Write down what error you saw and which layer produced it (wallet, node, mempool, peer)

That habit turns reading into builder instinct.

Glossary check

Pick three terms from this lesson and define them in one sentence each without opening notes. Weak definitions mean the lesson is not finished yet.

Resource order

Use Resources in order: narrative book chapter first, then BIP/BOLT for precision, then implementation docs for commands. Jumping straight to RPC flags without the mental model creates brittle knowledge.

Next steps

Learn how unconfirmed transactions compete in the mempool and how fee bumping works.