module Bitcoin::Multisig

utility for multisig

Public Class Methods

add_sig_to_multisig_script_sig(sig_to_add, script_sig, hash_type = SIGHASH_TYPE[:all]) click to toggle source

take a multisig script sig (or p2sh multisig script sig) and add another signature to it after the OP_0. Used to sign a tx by multiple parties. Signatures must be in the same order as the pubkeys in the output script being redeemed.

# File lib/bitcoin/script/multisig.rb, line 25
def self.add_sig_to_multisig_script_sig(sig_to_add, script_sig, hash_type = SIGHASH_TYPE[:all])
  signature = sig_to_add + [hash_type].pack("C*")
  offset = script_sig.empty? ? 0 : 1
  script_sig.insert(offset, Bitcoin::Script.pack_pushdata(signature))
end
add_sig_to_multisig_script_witness(sig_to_add, script_witness, hash_type = SIGHASH_TYPE[:all]) click to toggle source
# File lib/bitcoin/script/multisig.rb, line 65
def self.add_sig_to_multisig_script_witness(sig_to_add, script_witness, hash_type = SIGHASH_TYPE[:all])
  signature = sig_to_add + [hash_type].pack("C*")
  script_witness.stack << signature
end
prefix() click to toggle source
# File lib/bitcoin/script/multisig.rb, line 7
def self.prefix
  [OP_0].pack("C*")
end
sort_p2sh_multisig_signatures(script_sig, sig_hash) click to toggle source

Sort signatures in the given script_sig according to the order of pubkeys in the redeem script. Also needs the sig_hash to match signatures to pubkeys. @param [String] signature for multisig. @param [String] sig_hash to be signed. @return [String] sorted sig_hash.

# File lib/bitcoin/script/multisig.rb, line 46
def self.sort_p2sh_multisig_signatures(script_sig, sig_hash)
  script = Bitcoin::Script.parse_from_payload(script_sig)
  redeem_script = Bitcoin::Script.parse_from_payload(script.chunks[-1].pushed_data)
  pubkeys = redeem_script.get_multisig_pubkeys

  # find the pubkey for each signature by trying to verify it
  sigs = Hash[script.chunks[1...-1].map.with_index do |sig, idx|
    sig = sig.pushed_data
    pubkey = pubkeys.map do |key|
      Bitcoin::Key.new(pubkey: key.bth).verify(sig, sig_hash) ? key : nil
    end.compact.first
    raise "Key for signature ##{idx} not found in redeem script!"  unless pubkey
    [pubkey, sig]
  end]

  prefix + pubkeys.map { |k| sigs[k] ? Bitcoin::Script.pack_pushdata(sigs[k]) : nil }.join +
    Bitcoin::Script.pack_pushdata(script.chunks[-1].pushed_data)
end
sort_witness_multisig_signatures(script_witness, sig_hash) click to toggle source

Sort signatures in the given script_witness according to the order of pubkeys in the redeem script. Also needs the sig_hash to match signatures to pubkeys. @param [ScriptWitness] script_witness for multisig. @param [String] sig_hash to be signed.

# File lib/bitcoin/script/multisig.rb, line 74
def self.sort_witness_multisig_signatures(script_witness, sig_hash)
  redeem_script = Bitcoin::Script.parse_from_payload(script_witness.stack[-1])
  pubkeys = redeem_script.get_multisig_pubkeys
  sigs = Hash[script_witness.stack[1...-1].map.with_index do |sig, idx|
    pubkey = pubkeys.map do |key|
      Bitcoin::Key.new(pubkey: key.bth).verify(sig, sig_hash) ? key : nil
    end.compact.first
    raise "Key for signature ##{idx} not found in redeem script!"  unless pubkey
    [pubkey, sig]
  end]
  script_witness.stack.clear
  script_witness.stack << ''
  pubkeys.each do |pubkey|
    script_witness.stack << sigs[pubkey] if sigs[pubkey]
  end
  script_witness.stack << redeem_script.to_payload
end
to_multisig_script_sig(*sigs) click to toggle source

generate input script sig spending a multisig output script. returns a raw binary script sig of the form:

OP_0 <sig> [<sig> ...]

@param [[String]] array of signatures @return [String] script_sig for multisig

# File lib/bitcoin/script/multisig.rb, line 16
def self.to_multisig_script_sig(*sigs)
  hash_type = sigs.last.is_a?(Numeric) ? sigs.pop : SIGHASH_TYPE[:all]
  sigs.reverse.inject(prefix) { |joined, sig| add_sig_to_multisig_script_sig(sig, joined, hash_type) }
end
to_p2sh_multisig_script_sig(redeem_script, *sigs) click to toggle source

generate input script sig spending a p2sh-multisig output script. returns a raw binary script sig of the form:

OP_0 <sig> [<sig> ...] <redeem_script>

@param [Script] redeem_script @param [[String]] array of signatures @return [String] script_sig for multisig

# File lib/bitcoin/script/multisig.rb, line 37
def self.to_p2sh_multisig_script_sig(redeem_script, *sigs)
  to_multisig_script_sig(*sigs.flatten) + Bitcoin::Script.pack_pushdata(redeem_script)
end