class Bitcoin::ExtPubkey

BIP-32 Extended public key

Attributes

chain_code[RW]
depth[RW]
number[RW]
parent_fingerprint[RW]
pubkey[RW]
ver[RW]

Public Class Methods

encode_base58(hex) click to toggle source

Generate Base58 encoded key from BIP32 payload with hex format. @param [String] hex BIP32 payload with hex format. @return [String] Base58 encoded extended key.

# File lib/bitcoin/ext_key.rb, line 262
def self.encode_base58(hex)
  Base58.encode(hex + Bitcoin.calc_checksum(hex))
end
from_base58(address) click to toggle source

import pub key from Base58 private key address

# File lib/bitcoin/ext_key.rb, line 334
def self.from_base58(address)
  ExtPubkey.parse_from_payload(ExtPubkey.validate_base58(address))
end
parse_from_payload(payload) click to toggle source
# File lib/bitcoin/ext_key.rb, line 314
def self.parse_from_payload(payload)
  buf = StringIO.new(payload)
  ext_pubkey = ExtPubkey.new
  ext_pubkey.ver = buf.read(4).bth # version
  raise ArgumentError, Errors::Messages::INVALID_BIP32_VERSION unless ExtPubkey.support_version?(ext_pubkey.ver)
  ext_pubkey.depth = buf.read(1).unpack1('C')
  ext_pubkey.parent_fingerprint = buf.read(4).bth
  ext_pubkey.number = buf.read(4).unpack1('N')
  if ext_pubkey.depth == 0
    raise ArgumentError, Errors::Messages::INVALID_BIP32_FINGERPRINT unless ext_pubkey.parent_fingerprint == ExtKey::MASTER_FINGERPRINT
    raise ArgumentError, Errors::Messages::INVALID_BIP32_ZERO_INDEX if ext_pubkey.number > 0
  end
  raise ArgumentError, Errors::Messages::INVALID_BIP32_ZERO_DEPTH if ext_pubkey.parent_fingerprint == ExtKey::MASTER_FINGERPRINT && ext_pubkey.depth > 0
  ext_pubkey.chain_code = buf.read(32)
  ext_pubkey.pubkey = Bitcoin::Key.new(pubkey: buf.read(33).bth).pubkey
  ext_pubkey
end
support_version?(version) click to toggle source

check whether version is supported version bytes.

# File lib/bitcoin/ext_key.rb, line 361
def self.support_version?(version)
  p = Bitcoin.chain_params
  [p.bip49_pubkey_p2wpkh_p2sh_version, p.bip84_pubkey_p2wpkh_version, p.extended_pubkey_version].include?(version)
end
validate_base58(address) click to toggle source

Validate address checksum and return payload. @param [String] BIP32 Base58 address @return [String] BIP32 payload with binary format

# File lib/bitcoin/ext_key.rb, line 341
def self.validate_base58(address)
  raw = Base58.decode(address)
  raise ArgumentError, Errors::Messages::INVALID_CHECKSUM unless Bitcoin.calc_checksum(raw[0...-8]) == raw[-8..-1]
  raw[0...-8].htb
end
version_from_purpose(purpose) click to toggle source

get version bytes from purpose' value.

# File lib/bitcoin/ext_key.rb, line 348
def self.version_from_purpose(purpose)
  v = purpose - Bitcoin::HARDENED_THRESHOLD
  case v
    when 49
      Bitcoin.chain_params.bip49_pubkey_p2wpkh_p2sh_version
    when 84
      Bitcoin.chain_params.bip84_pubkey_p2wpkh_version
    else
      Bitcoin.chain_params.extended_pubkey_version
  end
end

Public Instance Methods

==(other) click to toggle source
# File lib/bitcoin/ext_key.rb, line 310
def ==(other)
  to_payload == other.to_payload
end
addr() click to toggle source

get address

# File lib/bitcoin/ext_key.rb, line 227
def addr
  case version
    when Bitcoin.chain_params.bip49_pubkey_p2wpkh_p2sh_version
      key.to_nested_p2wpkh
    when Bitcoin.chain_params.bip84_pubkey_p2wpkh_version
      key.to_p2wpkh
    else
      key.to_p2pkh
  end
end
derive(number) click to toggle source

derive child key

# File lib/bitcoin/ext_key.rb, line 272
def derive(number)
  new_key = ExtPubkey.new
  new_key.depth = depth + 1
  raise IndexError, 'Depth over 255.' if new_key.depth > Bitcoin::ExtKey::MAX_DEPTH
  new_key.number = number
  new_key.parent_fingerprint = fingerprint
  raise 'hardened key is not support' if number > (Bitcoin::HARDENED_THRESHOLD - 1)
  data = pub.htb << [number].pack('N')
  l = Bitcoin.hmac_sha512(chain_code, data)
  left = l[0..31].bth.to_i(16)
  raise 'invalid key' if left >= CURVE_ORDER
  p1 = Bitcoin::Key.new(priv_key: left.to_s(16), key_type: Bitcoin::Key::TYPES[:uncompressed]).to_point
  p2 = Bitcoin::Key.new(pubkey: pubkey, key_type: key_type).to_point
  new_key.pubkey = (p1 + p2).to_hex
  new_key.chain_code = l[32..-1]
  new_key.ver = version
  new_key
end
fingerprint() click to toggle source

get fingerprint

# File lib/bitcoin/ext_key.rb, line 250
def fingerprint
  identifier.slice(0..7)
end
hardened?() click to toggle source

whether hardened key.

# File lib/bitcoin/ext_key.rb, line 267
def hardened?
  number >= Bitcoin::HARDENED_THRESHOLD
end
hash160() click to toggle source
# File lib/bitcoin/ext_key.rb, line 222
def hash160
  Bitcoin.hash160(pub)
end
identifier() click to toggle source

get key identifier

# File lib/bitcoin/ext_key.rb, line 245
def identifier
  Bitcoin.hash160(pub)
end
key() click to toggle source

get key object @return [Bitcoin::Key]

# File lib/bitcoin/ext_key.rb, line 240
def key
  Bitcoin::Key.new(pubkey: pubkey, key_type: key_type)
end
key_type() click to toggle source

get key type defined by BIP-178 using version.

# File lib/bitcoin/ext_key.rb, line 298
def key_type
  v = version
  case v
  when Bitcoin.chain_params.bip49_pubkey_p2wpkh_p2sh_version
    Bitcoin::Key::TYPES[:p2wpkh_p2sh]
  when Bitcoin.chain_params.bip84_pubkey_p2wpkh_version
    Bitcoin::Key::TYPES[:p2wpkh]
  when Bitcoin.chain_params.extended_pubkey_version
    Bitcoin::Key::TYPES[:compressed]
  end
end
pub() click to toggle source
# File lib/bitcoin/ext_key.rb, line 218
def pub
  pubkey
end
to_base58() click to toggle source

Base58 encoded extended pubkey

# File lib/bitcoin/ext_key.rb, line 255
def to_base58
  ExtPubkey.encode_base58(to_hex)
end
to_payload() click to toggle source

serialize extended pubkey

# File lib/bitcoin/ext_key.rb, line 213
def to_payload
  version.htb << [depth].pack('C') <<
      parent_fingerprint.htb << [number].pack('N') << chain_code << pub.htb
end
version() click to toggle source

get version bytes using serialization format

# File lib/bitcoin/ext_key.rb, line 292
def version
  return ExtPubkey.version_from_purpose(number) if depth == 1
  ver ? ver : Bitcoin.chain_params.extended_pubkey_version
end