Class: Bitcoin::Protocol::Tx

Inherits:
Object
  • Object
show all
Defined in:
lib/segwit/tx.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data = nil) ⇒ Tx

create tx from raw binary data



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# File 'lib/segwit/tx.rb', line 14

def initialize(data=nil)
  @ver, @lock_time, @in, @out, @scripts, @witness = 1, 0, [], [], [], TxWitness.new
  @enable_bitcoinconsensus = !!ENV['USE_BITCOINCONSENSUS']
  if data
    begin
      parse_witness_data_from_io(data) unless parse_data_from_io(data).is_a?(TrueClass)
    rescue Exception
      parse_witness_data_from_io(data)
    end
  end
end

Instance Attribute Details

#witness ⇒ Object (readonly)

witness (TxWitness)



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# File 'lib/segwit/tx.rb', line 11

def witness
  @witness
end

Class Method Details

.binary_from_hash(h) ⇒ Object

convert ruby hash to raw binary



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# File 'lib/segwit/tx.rb', line 223

def self.binary_from_hash(h)
  tx = from_hash(h)
  tx.witness.empty? ? tx.to_payload : tx.to_witness_payload
end

.from_hash(h, do_raise = true) ⇒ Object

parse ruby hash (see also #to_hash)



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# File 'lib/segwit/tx.rb', line 205

def self.from_hash(h, do_raise=true)
  tx = new(nil)
  tx.ver, tx.lock_time = (h['ver'] || h['version']), h['lock_time']
  ins  = h['in']  || h['inputs']
  outs = h['out'] || h['outputs']
  ins .each{|input|
    tx.add_in(TxIn.from_hash(input))
    tx.witness.add_witness(TxInWitness.from_hash(input['witness'])) if input['witness']
  }
  outs.each{|output|  tx.add_out TxOut.from_hash(output) }
  tx.instance_eval{ @hash = hash_from_payload(@payload = to_payload) }
  if h['hash'] && (h['hash'] != tx.hash)
    raise "Tx hash mismatch! Claimed: #{h['hash']}, Actual: #{tx.hash}" if do_raise
  end
  tx
end

Instance Method Details

#parse_witness_data_from_io(data) ⇒ Object Also known as: parse_witness_data

parse witness raw binary data serialization format is defined by github.com/bitcoin/bips/blob/master/bip-0144.mediawiki



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# File 'lib/segwit/tx.rb', line 28

def parse_witness_data_from_io(data)
  buf = data.is_a?(String) ? StringIO.new(data) : data

  @ver = buf.read(4).unpack("V").first

  @marker = buf.read(1).unpack("c").first

  @flag = buf.read(1).unpack("c").first

  in_size = Bitcoin::Protocol.unpack_var_int_from_io(buf)
  @in = []
  in_size.times{
    break if buf.eof?
    @in << Bitcoin::Protocol::TxIn.from_io(buf)
  }

  out_size = Bitcoin::Protocol.unpack_var_int_from_io(buf)
  @out = []
  out_size.times{
    break if buf.eof?
    @out << Bitcoin::Protocol::TxOut.from_io(buf)
  }

  @witness = Bitcoin::Protocol::TxWitness.new
  in_size.times{
    witness_count = Bitcoin::Protocol.unpack_var_int_from_io(buf)
    in_witness = Bitcoin::Protocol::TxInWitness.new
    witness_count.times{
      length = Bitcoin::Protocol.unpack_var_int_from_io(buf)
      in_witness.add_stack(buf.read(length).unpack("H*").first)
    }
    @witness.add_witness(in_witness)
  }

  @lock_time = buf.read(4).unpack("V").first

  @hash = hash_from_payload(to_payload)

  if buf.eof?
    true
  else
    data.is_a?(StringIO) ? buf : buf.read
  end
end

#signature_hash_for_witness_input(input_idx, witness_program, prev_out_value, witness_script = nil, hash_type = nil, skip_separator_index = 0) ⇒ Object

generate a witness signature hash for input input_idx. github.com/bitcoin/bips/blob/master/bip-0143.mediawiki



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# File 'lib/segwit/tx.rb', line 87

def signature_hash_for_witness_input(input_idx, witness_program, prev_out_value, witness_script = nil, hash_type=nil, skip_separator_index = 0)
  return "\x01".ljust(32, "\x00") if input_idx >= @in.size # ERROR: SignatureHash() : input_idx=%d out of range

  hash_type ||= SIGHASH_TYPE[:all]

  script = Bitcoin::Script.new(witness_program)
  raise "ScriptPubkey does not contain witness program." unless script.is_witness?

  hash_prevouts = Digest::SHA256.digest(Digest::SHA256.digest(@in.map{|i| [i.prev_out_hash, i.prev_out_index].pack("a32V")}.join))
  hash_sequence = Digest::SHA256.digest(Digest::SHA256.digest(@in.map{|i|i.sequence}.join))
  outpoint = [@in[input_idx].prev_out_hash, @in[input_idx].prev_out_index].pack("a32V")
  amount = [prev_out_value].pack("Q")
  nsequence = @in[input_idx].sequence

  if script.is_witness_v0_keyhash?
    script_code = [["1976a914", script.get_hash160, "88ac"].join].pack("H*")
  elsif script.is_witness_v0_scripthash?
    raise "witness script does not match script pubkey" unless Bitcoin::Script.to_witness_p2sh_script(Digest::SHA256.digest(witness_script).bth) == witness_program
    script = skip_separator_index > 0 ? Bitcoin::Script.new(witness_script).subscript_codeseparator(skip_separator_index) : witness_script
    script_code = Bitcoin::Protocol.pack_var_string(script)
  end

  hash_outputs = Digest::SHA256.digest(Digest::SHA256.digest(@out.map{|o|o.to_payload}.join))

  case (hash_type & 0x1f)
    when SIGHASH_TYPE[:single]
      hash_outputs = input_idx >= @out.size ? "\x00".ljust(32, "\x00") : Digest::SHA256.digest(Digest::SHA256.digest(@out[input_idx].to_payload))
      hash_sequence = "\x00".ljust(32, "\x00")
    when SIGHASH_TYPE[:none]
      hash_sequence = hash_outputs = "\x00".ljust(32, "\x00")
  end

  if (hash_type & SIGHASH_TYPE[:anyonecanpay]) != 0
    hash_prevouts = hash_sequence ="\x00".ljust(32, "\x00")
  end

  buf = [ [@ver].pack("V"), hash_prevouts, hash_sequence, outpoint,
          script_code, amount, nsequence, hash_outputs, [@lock_time, hash_type].pack("VV")].join

  Digest::SHA256.digest( Digest::SHA256.digest( buf ) )
end

#to_hash(options = {}) ⇒ Object

convert to ruby hash (see also #from_hash)



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# File 'lib/segwit/tx.rb', line 187

def to_hash(options = {})
  @hash ||= hash_from_payload(to_payload)
  h = {
    'hash' => @hash, 'ver' => @ver, # 'nid' => normalized_hash,
    'vin_sz' => @in.size, 'vout_sz' => @out.size,
    'lock_time' => @lock_time, 'size' => (@payload ||= to_payload).bytesize,
    'in'  =>  @in.map.with_index{|i, index|
      h = i.to_hash(options)
      h.merge!('witness' => @witness.tx_in_wit[index].stack) if @witness.tx_in_wit[index]
      h
    },
    'out' => @out.map{|o| o.to_hash(options) }
  }
  h['nid'] = normalized_hash  if options[:with_nid]
  h
end

#to_witness_payload ⇒ Object

output transaction in raw binary format with witness



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# File 'lib/segwit/tx.rb', line 76

def to_witness_payload
  pin = ""
  @in.each{|input| pin << input.to_payload }
  pout = ""
  @out.each{|output| pout << output.to_payload }
  [@ver].pack("V") << [0].pack("c") << [1].pack("c") << Bitcoin::Protocol.pack_var_int(@in.size) << pin <<
      Bitcoin::Protocol.pack_var_int(@out.size) << pout << @witness.to_payload << [@lock_time].pack("V")
end

#verify_witness_input_signature(in_idx, outpoint_tx_or_script, prev_out_amount, block_timestamp = Time.now.to_i, opts = {}) ⇒ Object

verify witness input signature in_idx against the corresponding output in outpoint_tx outpoint

options are: verify_sigpushonly, verify_minimaldata, verify_cleanstack, verify_dersig, verify_low_s, verify_strictenc



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# File 'lib/segwit/tx.rb', line 134

def verify_witness_input_signature(in_idx, outpoint_tx_or_script, prev_out_amount, block_timestamp=Time.now.to_i, opts={})
  if @enable_bitcoinconsensus
    return bitcoinconsensus_verify_script(in_idx, outpoint_tx_or_script, block_timestamp, opts)
  end

  outpoint_idx  = @in[in_idx].prev_out_index
  script_sig    = ''

  # If given an entire previous transaction, take the script from it
  script_pubkey = if outpoint_tx_or_script.respond_to?(:out)
    Bitcoin::Script.new(outpoint_tx_or_script.out[outpoint_idx].pk_script)
  else
    # Otherwise, it's already a script.
    Bitcoin::Script.new(outpoint_tx_or_script)
  end

  if script_pubkey.is_p2sh?
    redeem_script = Bitcoin::Script.new(@in[in_idx].script_sig).get_pubkey
    script_pubkey = Bitcoin::Script.new(redeem_script.htb) if Bitcoin.hash160(redeem_script) == script_pubkey.get_hash160 # P2SH-P2WPKH or P2SH-P2WSH
  end

  witness.tx_in_wit[in_idx].stack.each{|s|script_sig << Bitcoin::Script.pack_pushdata(s.htb)}
  code_separator_index = 0

  if script_pubkey.is_witness_v0_keyhash? # P2WPKH
    @scripts[in_idx] = Bitcoin::Script.new(script_sig, Bitcoin::Script.to_hash160_script(script_pubkey.get_hash160))
  elsif script_pubkey.is_witness_v0_scripthash? # P2WSH
    witness_hex = witness.tx_in_wit[in_idx].stack.last
    witness_script = Bitcoin::Script.new(witness_hex.htb)
    return false unless Bitcoin.sha256(witness_hex) == script_pubkey.get_hash160
    @scripts[in_idx] = Bitcoin::Script.new(script_sig, Bitcoin::Script.to_p2sh_script(Bitcoin.hash160(witness_hex)))
  else
    return false
  end

  return false if opts[:verify_sigpushonly] && !@scripts[in_idx].is_push_only?(script_sig)
  return false if opts[:verify_minimaldata] && !@scripts[in_idx].pushes_are_canonical?
  sig_valid = @scripts[in_idx].run(block_timestamp, opts) do |pubkey,sig,hash_type,subscript|
    if script_pubkey.is_witness_v0_keyhash?
      hash = signature_hash_for_witness_input(in_idx, script_pubkey.to_payload, prev_out_amount, nil, hash_type)
    elsif script_pubkey.is_witness_v0_scripthash?
      hash = signature_hash_for_witness_input(in_idx, script_pubkey.to_payload, prev_out_amount, witness_hex.htb, hash_type, code_separator_index)
      code_separator_index += 1 if witness_script.codeseparator_count > code_separator_index
    end
    Bitcoin.verify_signature( hash, sig, pubkey.unpack("H*")[0] )
  end
  # BIP62 rule #6
  return false if opts[:verify_cleanstack] && !@scripts[in_idx].stack.empty?

  return sig_valid
end

#witness_hash ⇒ Object

get witness hash



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# File 'lib/segwit/tx.rb', line 229

def witness_hash
  hash_from_payload(to_witness_payload)
end