This page hosts a formal specification of Bitcoin Transaction using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for Ruby generated by Kaitai Struct depends on the Ruby runtime library. You have to install it before you can parse data.
The Ruby runtime library can be installed from RubyGems:
gem install kaitai-struct
Parse a local file and get structure in memory:
data = BitcoinTransaction.from_file("path/to/local/file.bin")
Or parse structure from a string of bytes:
bytes = "\x00\x01\x02..."
data = BitcoinTransaction.new(Kaitai::Struct::Stream.new(bytes))
After that, one can get various attributes from the structure by invoking getter methods like:
data.version # => Version number.
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
require 'kaitai/struct/struct'
unless Gem::Version.new(Kaitai::Struct::VERSION) >= Gem::Version.new('0.9')
raise "Incompatible Kaitai Struct Ruby API: 0.9 or later is required, but you have #{Kaitai::Struct::VERSION}"
end
##
# @see https://bitcoin.org/en/developer-guide#transactions
# https://en.bitcoin.it/wiki/Transaction
# Source
class BitcoinTransaction < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@version = @_io.read_u4le
@num_vins = @_io.read_u1
@vins = []
(num_vins).times { |i|
@vins << Vin.new(@_io, self, @_root)
}
@num_vouts = @_io.read_u1
@vouts = []
(num_vouts).times { |i|
@vouts << Vout.new(@_io, self, @_root)
}
@locktime = @_io.read_u4le
self
end
class Vin < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@txid = @_io.read_bytes(32)
@output_id = @_io.read_u4le
@len_script = @_io.read_u1
@_raw_script_sig = @_io.read_bytes(len_script)
_io__raw_script_sig = Kaitai::Struct::Stream.new(@_raw_script_sig)
@script_sig = ScriptSignature.new(_io__raw_script_sig, self, @_root)
@end_of_vin = @_io.read_bytes(4)
raise Kaitai::Struct::ValidationNotEqualError.new([255, 255, 255, 255].pack('C*'), end_of_vin, _io, "/types/vin/seq/4") if not end_of_vin == [255, 255, 255, 255].pack('C*')
self
end
class ScriptSignature < Kaitai::Struct::Struct
SIGHASH_TYPE = {
1 => :sighash_type_sighash_all,
2 => :sighash_type_sighash_none,
3 => :sighash_type_sighash_single,
80 => :sighash_type_sighash_anyonecanpay,
}
I__SIGHASH_TYPE = SIGHASH_TYPE.invert
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@len_sig_stack = @_io.read_u1
@der_sig = DerSignature.new(@_io, self, @_root)
@sig_type = Kaitai::Struct::Stream::resolve_enum(SIGHASH_TYPE, @_io.read_u1)
@len_pubkey_stack = @_io.read_u1
@pubkey = PublicKey.new(@_io, self, @_root)
self
end
class DerSignature < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@sequence = @_io.read_bytes(1)
raise Kaitai::Struct::ValidationNotEqualError.new([48].pack('C*'), sequence, _io, "/types/vin/types/script_signature/types/der_signature/seq/0") if not sequence == [48].pack('C*')
@len_sig = @_io.read_u1
@sep_1 = @_io.read_bytes(1)
raise Kaitai::Struct::ValidationNotEqualError.new([2].pack('C*'), sep_1, _io, "/types/vin/types/script_signature/types/der_signature/seq/2") if not sep_1 == [2].pack('C*')
@len_sig_r = @_io.read_u1
@sig_r = @_io.read_bytes(len_sig_r)
@sep_2 = @_io.read_bytes(1)
raise Kaitai::Struct::ValidationNotEqualError.new([2].pack('C*'), sep_2, _io, "/types/vin/types/script_signature/types/der_signature/seq/5") if not sep_2 == [2].pack('C*')
@len_sig_s = @_io.read_u1
@sig_s = @_io.read_bytes(len_sig_s)
self
end
attr_reader :sequence
attr_reader :len_sig
attr_reader :sep_1
##
# 'r' value's length.
attr_reader :len_sig_r
##
# 'r' value of the ECDSA signature.
# @see https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm Source
attr_reader :sig_r
attr_reader :sep_2
##
# 's' value's length.
attr_reader :len_sig_s
##
# 's' value of the ECDSA signature.
# @see https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm Source
attr_reader :sig_s
end
class PublicKey < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@type = @_io.read_u1
@x = @_io.read_bytes(32)
@y = @_io.read_bytes(32)
self
end
attr_reader :type
##
# 'x' coordinate of the public key on the elliptic curve.
attr_reader :x
##
# 'y' coordinate of the public key on the elliptic curve.
attr_reader :y
end
attr_reader :len_sig_stack
##
# DER-encoded ECDSA signature.
# @see https://en.wikipedia.org/wiki/X.690#DER_encoding
# https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm
# Source
attr_reader :der_sig
##
# Type of signature.
attr_reader :sig_type
attr_reader :len_pubkey_stack
##
# Public key (bitcoin address of the recipient).
attr_reader :pubkey
end
##
# Previous transaction hash.
attr_reader :txid
##
# ID indexing an ouput of the transaction refered by txid.
# This output will be used as an input in the present transaction.
attr_reader :output_id
##
# ScriptSig's length.
attr_reader :len_script
##
# ScriptSig.
# @see https://en.bitcoin.it/wiki/Transaction#Input
# https://en.bitcoin.it/wiki/Script
# Source
attr_reader :script_sig
##
# Magic number indicating the end of the current input.
attr_reader :end_of_vin
attr_reader :_raw_script_sig
end
class Vout < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@amount = @_io.read_u8le
@len_script = @_io.read_u1
@script_pub_key = @_io.read_bytes(len_script)
self
end
##
# Number of Satoshis to be transfered.
attr_reader :amount
##
# ScriptPubKey's length.
attr_reader :len_script
##
# ScriptPubKey.
# @see https://en.bitcoin.it/wiki/Transaction#Output
# https://en.bitcoin.it/wiki/Script
# Source
attr_reader :script_pub_key
end
##
# Version number.
attr_reader :version
##
# Number of input transactions.
attr_reader :num_vins
##
# Input transactions.
# An input refers to an output from a previous transaction.
attr_reader :vins
##
# Number of output transactions.
attr_reader :num_vouts
##
# Output transactions.
attr_reader :vouts
attr_reader :locktime
end