Class: Bitcoin::ExtPubkey

Inherits:
Object
  • Object
show all
Defined in:
lib/bitcoin/ext_key.rb

Overview

BIP-32 Extended public key

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#chain_code ⇒ Object

Returns the value of attribute chain_code.



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# File 'lib/bitcoin/ext_key.rb', line 124

def chain_code
  @chain_code
end

#depth ⇒ Object

Returns the value of attribute depth.



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# File 'lib/bitcoin/ext_key.rb', line 122

def depth
  @depth
end

#number ⇒ Object

Returns the value of attribute number.



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# File 'lib/bitcoin/ext_key.rb', line 123

def number
  @number
end

#parent_fingerprint ⇒ Object

Returns the value of attribute parent_fingerprint.



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# File 'lib/bitcoin/ext_key.rb', line 126

def parent_fingerprint
  @parent_fingerprint
end

#pub_key ⇒ Object

Returns the value of attribute pub_key.



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# File 'lib/bitcoin/ext_key.rb', line 125

def pub_key
  @pub_key
end

Class Method Details

.from_base58(address) ⇒ Object

import private key from Base58 private key address



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# File 'lib/bitcoin/ext_key.rb', line 178

def self.from_base58(address)
  data = StringIO.new(Bitcoin.decode_base58(address).htb)
  key = ExtPubkey.new
  data.read(4).bth # version
  key.depth = data.read(1).unpack('C').first
  key.parent_fingerprint = data.read(4).bth
  key.number = data.read(4).unpack('N').first
  key.chain_code = data.read(32)
  key.pub_key = OpenSSL::PKey::EC::Point.from_hex(Bitcoin.bitcoin_elliptic_curve.group, data.read(33).bth)
  key
end

Instance Method Details

#addr ⇒ Object

get address



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# File 'lib/bitcoin/ext_key.rb', line 140

def addr
  Bitcoin.hash160_to_address(Bitcoin.hash160(pub))
end

#derive(number) ⇒ Object

derive child key



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# File 'lib/bitcoin/ext_key.rb', line 162

def derive(number)
  new_key = ExtPubkey.new
  new_key.depth = depth + 1
  new_key.number = number
  new_key.parent_fingerprint = fingerprint
  raise 'hardened key is not support' if number > (2**31 - 1)
  data = pub.htb << [number].pack('N')
  l = Bitcoin.hmac_sha512(chain_code, data)
  left = OpenSSL::BN.from_hex(l[0..31].bth)
  raise 'invalid key' if left.to_i >= CURVE_ORDER
  new_key.pub_key = Bitcoin.bitcoin_elliptic_curve.group.generator.mul(left).ec_add(pub_key)
  new_key.chain_code = l[32..-1]
  new_key
end

#fingerprint ⇒ Object

get fingerprint



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# File 'lib/bitcoin/ext_key.rb', line 150

def fingerprint
  identifier.slice(0..7)
end

#identifier ⇒ Object

get key identifier



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# File 'lib/bitcoin/ext_key.rb', line 145

def identifier
  Bitcoin.hash160(pub)
end

#pub ⇒ Object

get public key(hex)



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# File 'lib/bitcoin/ext_key.rb', line 134

def pub
  pub_key.group.point_conversion_form = :compressed
  pub_key.to_hex.rjust(66, '0')
end

#to_base58 ⇒ Object

Base58 encoded extended pubkey



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# File 'lib/bitcoin/ext_key.rb', line 155

def to_base58
  h = to_payload.bth
  hex = h + Bitcoin.checksum(h)
  Bitcoin.encode_base58(hex)
end

#to_payload ⇒ Object

serialize extended pubkey



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# File 'lib/bitcoin/ext_key.rb', line 129

def to_payload
  Bitcoin.network[:extended_pubkey_version].htb << [depth].pack('C') << parent_fingerprint.htb << [number].pack('N') << chain_code << pub.htb
end