DUCAT’SBitcoin Guild
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COMPLETE SCRIPT GUIDE

Bitcoin Script from stack to spending policy

Script decides whether one input may spend one previous output. This guide begins with stack execution, then builds signatures, branches, hashes, timelocks, classic templates, native witness programs and nested SegWit forms.

10 connected lessons Practice in every lesson
01

See the whole system first

Each specialist lesson expands one relationship in this end-to-end map.

  1. 01
    Previous output

    ScriptPubKey commits the spending condition and value being spent.

  2. 02
    Input data

    ScriptSig and witness supply signatures, public keys, scripts and branch selectors.

  3. 03
    Stack execution

    Nodes apply opcodes in order under consensus limits and transaction context.

  4. 04
    Commitment checks

    Hashes bind revealed keys or scripts to what the output committed earlier.

  5. 05
    Authorization checks

    Signature opcodes verify the selected transaction digest and public key.

  6. 06
    Final result

    The input succeeds only if execution completes with a true top stack item.

You will be able to step through a stack trace, locate the first failed predicate, and build P2PK, P2PKH, P2MS, P2SH, OP_RETURN and native or nested SegWit forms.

02

Run the mechanism here

Predict first, execute exact bytes or rules, then change one input and inspect the first failed boundary.

EXACT MECHANISM WORKBENCH

Execute classic Bitcoin Script templates

Switch among P2PK, P2PKH, bare P2MS, P2SH, and OP_RETURN. The trace exposes the exact stack item, commitment, or failure boundary unique to each form.

Predict the result
Required cases complete: 0/10.
EDITABLE SCRIPT BYTES

Parse the output, unlock it, then execute P2WSH

The first tool classifies the previous output and states the exact spend data it requires. The second parses a length-prefixed ScriptSig and hands it to that output. The third compiles an editable witness program and executes its stack.

ScriptPubKey classifier

Ready to execute

Edit a fixture, predict the first changed field, then run it.

Length-prefixed ScriptSig

Ready to execute

Edit a fixture, predict the first changed field, then run it.

Editable P2WSH executor

Ready to execute

Edit a fixture, predict the first changed field, then run it.

5 LIVE BITCOIN UTILITIES

Calculate bitcoin script from stack to spending policy

Use real learner input rather than a prewritten answer. Every result is calculated locally from the fields shown and invalid data fails closed.

Hashes

HASH160

Apply SHA-256 then RIPEMD-160 to hexadecimal bytes.

Ready to calculate

Change any field, predict what should change, then run the utility.

Safety boundary: This learning surface does not store inputs. Never paste a live seed phrase, private key, wallet backup, or confidential transaction.

03

Follow the mechanism in order

Start at the top for a guided route, or open any lesson directly.

01

Stack-machine execution

Script is a deliberately constrained stack language whose success depends on final truth and consensus limits.

Teach, predict, run, explain
02

Pushes, arithmetic, and control flow

Data pushes, numeric encodings, conditionals, and verification opcodes compose spending policies.

Teach, predict, run, explain
03

Signature checks and sighashes

CHECKSIG validates a signature over a transaction digest selected by a sighash mode.

Teach, predict, run, explain
04

P2PKH and P2SH

Legacy templates separate address-friendly commitments from revealed spending scripts.

Teach, predict, run, explain
05

Witness programs

SegWit moves authorization data into witness structures and versions the program semantics.

Teach, predict, run, explain
06

Multisig and policy composition

Multiple keys, timelocks, and hashlocks can form recovery, escrow, and channel policies.

Teach, predict, run, explain
07

Script limits and malleability

Disabled opcodes, resource limits, encoding rules, and malleability protections constrain safe composition.

Teach, predict, run, explain
08

Script debugging

Experts trace every stack transition, identify the failing predicate, and distinguish malformed witnesses from false conditions.

Teach, predict, run, explain
09

P2PK, P2PKH, P2MS, P2SH, and OP_RETURN

Compare the exact assembly, serialized bytes, spend data, standard uses, and failure boundary for Bitcoin's classic Script templates.

Teach, predict, run, explain
10

Native and nested SegWit scripts

Construct P2WPKH, P2WSH, P2SH-P2WPKH, and P2SH-P2WSH outputs and follow each redeem, witness, hash, and signature check.

Teach, predict, run, explain
04

Keep these boundaries clear

These distinctions stop the most consequential mistakes in this topic.

  • Script has no authority outside the transaction and previous output it is evaluating.
  • P2SH and P2WSH first prove that the revealed script matches a hash, then execute that script.
  • Standard relay policy can be stricter than consensus acceptance.