module Bitcoin::Util

bitcoin utility. following methods can be used as follows.

Bitcoin.pack_var_int(5)

Constants

DIGEST_NAME_SHA256

Public Instance Methods

byte_to_bit(byte) click to toggle source

byte convert to the sequence of bits packed eight in a byte with the least significant bit first.

# File lib/bitcoin/util.rb, line 81
def byte_to_bit(byte)
  byte.unpack1('b*')
end
calc_checksum(hex) click to toggle source
# File lib/bitcoin/util.rb, line 130
def calc_checksum(hex)
  double_sha256(hex.htb).bth[0..7]
end
decode_base58_address(addr) click to toggle source

decode Base58 check encoding address. @param [String] addr address. @return [Array] hex and address version

# File lib/bitcoin/util.rb, line 120
def decode_base58_address(addr)
  hex = Base58.decode(addr)
  if hex.size == 50 && calc_checksum(hex[0...-8]) == hex[-8..-1]
    raise 'Invalid version bytes.' unless [Bitcoin.chain_params.address_version, Bitcoin.chain_params.p2sh_version].include?(hex[0..1])
    [hex[2...-8], hex[0..1]]
  else
    raise 'Invalid address.'
  end
end
double_sha256(payload) click to toggle source
# File lib/bitcoin/util.rb, line 76
def double_sha256(payload)
  sha256(sha256(payload))
end
encode_base58_address(hex, addr_version) click to toggle source

encode Base58 check address. @param [String] hex the address payload. @param [String] addr_version the address version for P2PKH and P2SH. @return [String] Base58 check encoding address.

# File lib/bitcoin/util.rb, line 112
def encode_base58_address(hex, addr_version)
  base = addr_version + hex
  Base58.encode(base + calc_checksum(base))
end
hash160(hex) click to toggle source

generate sha256-ripemd160 hash for value

# File lib/bitcoin/util.rb, line 95
def hash160(hex)
  Digest::RMD160.hexdigest(Digest::SHA256.digest(hex.htb))
end
hmac_sha256(key, data) click to toggle source
# File lib/bitcoin/util.rb, line 136
def hmac_sha256(key, data)
  OpenSSL::HMAC.digest(DIGEST_NAME_SHA256, key, data)
end
pack_boolean(b) click to toggle source
# File lib/bitcoin/util.rb, line 63
def pack_boolean(b)
  b ? [0x01].pack('C') : [0x00].pack('C')
end
pack_var_int(i) click to toggle source
# File lib/bitcoin/util.rb, line 20
def pack_var_int(i)
  if i <  0xfd
    [i].pack('C')
  elsif i <= 0xffff
    [0xfd, i].pack('Cv')
  elsif i <= 0xffffffff
    [0xfe, i].pack('CV')
  elsif i <= 0xffffffffffffffff
    [0xff, i].pack('CQ')
  else
    raise "int(#{i}) too large!"
  end
end
pack_var_string(payload) click to toggle source
# File lib/bitcoin/util.rb, line 11
def pack_var_string(payload)
  pack_var_int(payload.bytesize) + payload
end
padding_zero(binary, bytesize) click to toggle source

padding zero to the left of binary string until bytesize. @param [String] binary string @param [Integer] bytesize total bytesize. @return [String] padded binary string.

# File lib/bitcoin/util.rb, line 89
def padding_zero(binary, bytesize)
  return binary unless binary.bytesize < bytesize
  ('00' * (bytesize - binary.bytesize)).htb + binary
end
sha256(payload) click to toggle source
# File lib/bitcoin/util.rb, line 72
def sha256(payload)
  Digest::SHA256.digest(payload)
end
tagged_hash(tag, msg) click to toggle source

Generate tagged hash value. @param [String] tag tag value. @param [String] msg the message to be hashed. @return [String] the hash value with binary format.

# File lib/bitcoin/util.rb, line 103
def tagged_hash(tag, msg)
  tag_hash = Digest::SHA256.digest(tag)
  Digest::SHA256.digest(tag_hash + tag_hash + msg)
end
unpack_boolean(payload) click to toggle source
# File lib/bitcoin/util.rb, line 67
def unpack_boolean(payload)
  data, payload = payload.unpack('Ca*')
  [(data.zero? ? false : true), payload]
end
unpack_var_int(payload) click to toggle source

@return an integer for a valid payload, otherwise nil

# File lib/bitcoin/util.rb, line 35
def unpack_var_int(payload)
  case payload.unpack1('C')
  when 0xfd
    payload.unpack('xva*')
  when 0xfe
    payload.unpack('xVa*')
  when 0xff
    payload.unpack('xQa*')
  else
    payload.unpack('Ca*')
  end
end
unpack_var_int_from_io(buf) click to toggle source

@return an integer for a valid payload, otherwise nil

# File lib/bitcoin/util.rb, line 49
def unpack_var_int_from_io(buf)
  uchar = buf.read(1)&.unpack1('C')
  case uchar
  when 0xfd
    buf.read(2)&.unpack1('v')
  when 0xfe
    buf.read(4)&.unpack1('V')
  when 0xff
    buf.read(8)&.unpack1('Q')
  else
    uchar
  end
end
unpack_var_string(payload) click to toggle source
# File lib/bitcoin/util.rb, line 15
def unpack_var_string(payload)
  size, payload = unpack_var_int(payload)
  size > 0 ? payload.unpack("a#{size}a*") : [nil, payload]
end
valid_address?(addr) click to toggle source

check whether addr is valid address. @param [String] addr an address @return [Boolean] if valid address return true, otherwise false.

# File lib/bitcoin/util.rb, line 143
def valid_address?(addr)
  begin
    Bitcoin::Script.parse_from_addr(addr)
    true
  rescue Exception
    false
  end
end