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Script: add function for parsing multisig type scripts

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This commit is contained in:
Thomas Kerin 2016-10-27 13:32:51 +02:00 • committed by Daniel Cousens
parent 405c005802
commit 53f08a7569
1 changed files with 52 additions and 31 deletions
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83
src/script.js
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@ -2,7 +2,6 @@ var bip66 = require('bip66')
var bufferutils = require('./bufferutils')
var typeforce = require('typeforce')
var types = require('./types')
var OPS = require('./opcodes.json')
var REVERSE_OPS = (function () {
var result = {}
@ -251,27 +250,55 @@ function isMultisigInput (script, allowIncomplete) {
return chunks.slice(1).every(isCanonicalSignature)
}
function parseMultisigScript (scriptPubKey) {
var chunks = decompile(scriptPubKey)
if (chunks.length < 4) {
throw new Error('Multisig script should contain at least 4 elements')
}
if (chunks[chunks.length - 1] !== OPS.OP_CHECKMULTISIG) {
throw new Error('Final opcode should be OP_CHECKMULTISIG')
}
if (!types.Number(chunks[0])) {
throw new Error('First element must be a number-push opcode')
}
if (!types.Number(chunks[chunks.length - 2])) {
throw new Error('Second-last element must be a number-push opcode')
}
var m = chunks[0] - OP_INT_BASE
var n = chunks[chunks.length - 2] - OP_INT_BASE
if (m <= 0) {
throw new Error('Number of signatures required must be greater than zero')
}
if (n > 16) {
throw new Error('Number of public keys must be less than 17')
}
if (m > n) {
throw new Error('Number of signatures cannot exceed the number of public keys')
}
if (n !== chunks.length - 3) {
throw new Error('n does not match the number of public keys')
}
var keys = chunks.slice(1, -2)
if (!keys.every(isCanonicalPubKey)) {
throw new Error('Non-canonical pubic key found')
}
return {
nRequiredSigs: m,
nPublicKeys: n,
publicKeyBuffers: keys
}
}
function isMultisigOutput (script) {
var chunks = decompile(script)
if (chunks.length < 4) return false
if (chunks[chunks.length - 1] !== OPS.OP_CHECKMULTISIG) return false
var mOp = chunks[0]
var nOp = chunks[chunks.length - 2]
if (!types.Number(mOp)) return false
if (!types.Number(nOp)) return false
var m = mOp - OP_INT_BASE
var n = nOp - OP_INT_BASE
// 0 < m <= n <= 16
if (m <= 0) return false
if (m > n) return false
if (n > 16) return false
if (n !== chunks.length - 3) return false
return chunks.slice(1, -2).every(isCanonicalPubKey)
try {
parseMultisigScript(script)
return true
} catch (e) {
return false
}
}
function isNullDataOutput (script) {
@ -399,16 +426,9 @@ function witnessScriptHashInput (scriptSig, scriptPubKey) {
// OP_0 [signatures ...]
function multisigInput (signatures, scriptPubKey) {
if (scriptPubKey) {
var chunks = decompile(scriptPubKey)
if (!isMultisigOutput(chunks)) throw new Error('Expected multisig scriptPubKey')
var mOp = chunks[0]
var nOp = chunks[chunks.length - 2]
var m = mOp - OP_INT_BASE
var n = nOp - OP_INT_BASE
if (signatures.length < m) throw new Error('Not enough signatures provided')
if (signatures.length > n) throw new Error('Too many signatures provided')
var scriptData = parseMultisigScript(scriptPubKey)
if (signatures.length < scriptData.nRequiredSigs) throw new Error('Not enough signatures provided')
if (signatures.length > scriptData.nPublicKeys) throw new Error('Too many signatures provided')
}
return compile([].concat(OPS.OP_0, signatures))
@ -441,6 +461,7 @@ module.exports = {
isMultisigOutput: isMultisigOutput,
isNullDataOutput: isNullDataOutput,
parseMultisigScript: parseMultisigScript,
classifyOutput: classifyOutput,
classifyInput: classifyInput,
pubKeyOutput: pubKeyOutput,