Class: Bitcoin::Key

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

Overview

bitcoin key class

Constant Summary collapse

PUBLIC_KEY_SIZE = 
65
COMPRESSED_PUBLIC_KEY_SIZE = 
33
SIGNATURE_SIZE = 
72
COMPACT_SIGNATURE_SIZE = 
65
COMPACT_SIG_HEADER_BYTE = 
0x1b
TYPES = 
{uncompressed: 0x00, compressed: 0x01, p2pkh: 0x10, p2wpkh: 0x11, p2wpkh_p2sh: 0x12}
MIN_PRIV_KEY_MOD_ORDER = 
0x01
MAX_PRIV_KEY_MOD_ORDER =

Order of secp256k1’s generator minus 1.

ECDSA::Group::Secp256k1.order - 1

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(priv_key: nil, pubkey: nil, key_type: nil, compressed: true, allow_hybrid: false) ⇒ Bitcoin::Key

initialize private key

Parameters:

  • priv_key (String) (defaults to: nil) —

    a private key with hex format.

  • pubkey (String) (defaults to: nil) —

    a public key with hex format.

  • key_type (Integer) (defaults to: nil) —

    a key type which determine address type.

  • compressed (Boolean) (defaults to: true) —
    Deprecated

    whether public key is compressed.

Raises:

  • (ArgumentError) 


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# File 'lib/bitcoin/key.rb', line 32

def initialize(priv_key: nil, pubkey: nil, key_type: nil, compressed: true, allow_hybrid: false)
  if key_type
    @key_type = key_type
    compressed = @key_type != TYPES[:uncompressed]
  else
    @key_type = compressed ? TYPES[:compressed] : TYPES[:uncompressed]
  end
  @secp256k1_module =  Bitcoin.secp_impl
  @priv_key = priv_key
  if @priv_key
    raise ArgumentError, Errors::Messages::INVALID_PRIV_KEY unless validate_private_key_range(@priv_key)
  end
  if pubkey
    @pubkey = pubkey
  else
    @pubkey = generate_pubkey(priv_key, compressed: compressed) if priv_key
  end
  raise ArgumentError, Errors::Messages::INVALID_PUBLIC_KEY unless fully_valid_pubkey?(allow_hybrid)
end

Instance Attribute Details

#key_type ⇒ Object

Returns the value of attribute key_type.



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# File 'lib/bitcoin/key.rb', line 17

def key_type
  @key_type
end

#priv_key ⇒ Object

Returns the value of attribute priv_key.



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# File 'lib/bitcoin/key.rb', line 15

def priv_key
  @priv_key
end

#pubkey ⇒ Object

Returns the value of attribute pubkey.



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# File 'lib/bitcoin/key.rb', line 16

def pubkey
  @pubkey
end

#secp256k1_module ⇒ Object (readonly)

Returns the value of attribute secp256k1_module.



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# File 'lib/bitcoin/key.rb', line 18

def secp256k1_module
  @secp256k1_module
end

Class Method Details

.compress_or_uncompress_pubkey?(pubkey) ⇒ Boolean

check pubkey (hex) is compress or uncompress pubkey.

Returns:

  • (Boolean) 


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# File 'lib/bitcoin/key.rb', line 219

def self.compress_or_uncompress_pubkey?(pubkey)
  p = pubkey.htb
  return false if p.bytesize < COMPRESSED_PUBLIC_KEY_SIZE
  case p[0]
    when "\x04"
      return false unless p.bytesize == PUBLIC_KEY_SIZE
    when "\x02", "\x03"
      return false unless p.bytesize == COMPRESSED_PUBLIC_KEY_SIZE
    else
      return false
  end
  true
end

.compress_pubkey?(pubkey) ⇒ Boolean

check pubkey (hex) is compress pubkey.

Returns:

  • (Boolean) 


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# File 'lib/bitcoin/key.rb', line 234

def self.compress_pubkey?(pubkey)
  p = pubkey.htb
  p.bytesize == COMPRESSED_PUBLIC_KEY_SIZE && ["\x02", "\x03"].include?(p[0])
end

.from_point(point, compressed: true) ⇒ Bitcoin::Key

Generate from public key point.

Parameters:

  • point (ECDSA::Point) —

    Public key point.

  • compressed (Boolean) (defaults to: true) —

    whether compressed or not.

Returns:



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# File 'lib/bitcoin/key.rb', line 92

def self.from_point(point, compressed: true)
  pubkey = ECDSA::Format::PointOctetString.encode(point, compression: compressed).bth
  Bitcoin::Key.new(pubkey: pubkey, key_type: TYPES[:compressed])
end

.from_wif(wif) ⇒ Object

import private key from wif format en.bitcoin.it/wiki/Wallet_import_format

Raises:

  • (ArgumentError) 


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# File 'lib/bitcoin/key.rb', line 60

def self.from_wif(wif)
  hex = Base58.decode(wif)
  raise ArgumentError, 'data is too short' if hex.htb.bytesize < 4
  version = hex[0..1]
  data = hex[2...-8].htb
  checksum = hex[-8..-1]
  raise ArgumentError, 'invalid version' unless version == Bitcoin.chain_params.privkey_version
  raise ArgumentError, Errors::Messages::INVALID_CHECKSUM unless Bitcoin.calc_checksum(version + data.bth) == checksum
  key_len = data.bytesize
  if key_len == COMPRESSED_PUBLIC_KEY_SIZE && data[-1].unpack1('C') == 1
    key_type = TYPES[:compressed]
    data = data[0..-2]
  elsif key_len == 32
    key_type = TYPES[:uncompressed]
  else
    raise ArgumentError, 'Wrong number of bytes for a private key, not 32 or 33'
  end
  new(priv_key: data.bth, key_type: key_type)
end

.from_xonly_pubkey(xonly_pubkey) ⇒ Bitcoin::Key

Generate from xonly public key.

Parameters:

  • xonly_pubkey (String) —

    xonly public key with hex format.

Returns:

Raises:

  • (ArgumentError) 


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# File 'lib/bitcoin/key.rb', line 83

def self.from_xonly_pubkey(xonly_pubkey)
  raise ArgumentError, 'xonly_pubkey must be 32 bytes' unless xonly_pubkey.htb.bytesize == 32
  Bitcoin::Key.new(pubkey: "02#{xonly_pubkey}", key_type: TYPES[:compressed])
end

.generate(key_type = TYPES[:compressed]) ⇒ Object

generate key pair



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# File 'lib/bitcoin/key.rb', line 53

def self.generate(key_type = TYPES[:compressed])
  priv_key, pubkey = Bitcoin.secp_impl.generate_key_pair
  new(priv_key: priv_key, pubkey: pubkey, key_type: key_type)
end

.low_signature?(sig) ⇒ Boolean

check sig is low.

Returns:

  • (Boolean) 


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# File 'lib/bitcoin/key.rb', line 240

def self.low_signature?(sig)
  s = sig.unpack('C*')
  len_r = s[3]
  len_s = s[5 + len_r]
  val_s = s.slice(6 + len_r, len_s)
  max_mod_half_order = [
      0x7f,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
      0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
      0x5d,0x57,0x6e,0x73,0x57,0xa4,0x50,0x1d,
      0xdf,0xe9,0x2f,0x46,0x68,0x1b,0x20,0xa0]
  compare_big_endian(val_s, [0]) > 0 &&
      compare_big_endian(val_s, max_mod_half_order) <= 0
end

.recover_compact(data, signature) ⇒ Bitcoin::Key

Recover public key from compact signature.

Parameters:

  • data (String) —

    message digest using signature.

  • signature (String) —

    signature with binary format.

Returns:

Raises:

  • (ArgumentError) 


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# File 'lib/bitcoin/key.rb', line 146

def self.recover_compact(data, signature)
  rec_id = signature.unpack1('C')
  rec = rec_id - Bitcoin::Key::COMPACT_SIG_HEADER_BYTE
  raise ArgumentError, 'Invalid signature parameter' if rec < 0 || rec > 15
  rec = rec & 3
  compressed = (rec_id - Bitcoin::Key::COMPACT_SIG_HEADER_BYTE) & 4 != 0
  Bitcoin.secp_impl.recover_compact(data, signature, rec, compressed)
end

.valid_signature_encoding?(sig) ⇒ Boolean

check sig is correct der encoding. This function is consensus-critical since BIP66.

Returns:

  • (Boolean) 


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# File 'lib/bitcoin/key.rb', line 257

def self.valid_signature_encoding?(sig)
  return false if sig.bytesize < 9 || sig.bytesize > 73 # Minimum and maximum size check

  s = sig.unpack('C*')

  return false if s[0] != 0x30 || s[1] != s.size - 3 # A signature is of type 0x30 (compound). Make sure the length covers the entire signature.

  len_r = s[3]
  return false if 5 + len_r >= s.size # Make sure the length of the S element is still inside the signature.

  len_s = s[5 + len_r]
  return false unless len_r + len_s + 7 == s.size #Verify that the length of the signature matches the sum of the length of the elements.

  return false unless s[2] == 0x02 # Check whether the R element is an integer.

  return false if len_r == 0 # Zero-length integers are not allowed for R.

  return false unless s[4] & 0x80 == 0 # Negative numbers are not allowed for R.

  # Null bytes at the start of R are not allowed, unless R would otherwise be interpreted as a negative number.
  return false if len_r > 1 && (s[4] == 0x00) && (s[5] & 0x80 == 0)

  return false unless s[len_r + 4] == 0x02 # Check whether the S element is an integer.

  return false if len_s == 0 # Zero-length integers are not allowed for S.
  return false unless (s[len_r + 6] & 0x80) == 0 # Negative numbers are not allowed for S.

  # Null bytes at the start of S are not allowed, unless S would otherwise be interpreted as a negative number.
  return false if len_s > 1 && (s[len_r + 6] == 0x00) && (s[len_r + 7] & 0x80 == 0)

  true
end

Instance Method Details

#compressed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/bitcoin/key.rb', line 200

def compressed?
  key_type != TYPES[:uncompressed]
end

#fully_valid_pubkey?(allow_hybrid = false) ⇒ Boolean

fully validate whether this is a valid public key (more expensive than IsValid())

Returns:

  • (Boolean) 


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# File 'lib/bitcoin/key.rb', line 291

def fully_valid_pubkey?(allow_hybrid = false)
  valid_pubkey? && secp256k1_module.parse_ec_pubkey?(pubkey, allow_hybrid)
end

#hash160 ⇒ Object

get hash160 public key.



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

def hash160
  Bitcoin.hash160(pubkey)
end

#sign(data, low_r = true, extra_entropy = nil, algo: :ecdsa) ⇒ String

sign data with private key

Parameters:

  • data (String) —

    a data to be signed with binary format

  • low_r (Boolean) (defaults to: true) —

    flag to apply low-R.

  • extra_entropy (String) (defaults to: nil) —

    the extra entropy with binary format for rfc6979.

  • algo (Symbol) (defaults to: :ecdsa) —

    signature algorithm. ecdsa(default) or schnorr.

Returns:

  • (String) —

    signature data with binary format



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# File 'lib/bitcoin/key.rb', line 112

def sign(data, low_r = true, extra_entropy = nil, algo: :ecdsa)
  case algo
  when :ecdsa
    sig = secp256k1_module.sign_data(data, priv_key, extra_entropy)
    if low_r && !sig_has_low_r?(sig)
      counter = 1
      until sig_has_low_r?(sig)
        extra_entropy = [counter].pack('I*').bth.ljust(64, '0').htb
        sig = secp256k1_module.sign_data(data, priv_key, extra_entropy)
        counter += 1
      end
    end
    sig
  when :schnorr
    secp256k1_module.sign_data(data, priv_key, extra_entropy, algo: :schnorr)
  else
    raise ArgumentError "Unsupported algo specified: #{algo}"
  end
end

#sign_compact(data) ⇒ String

Sign compact signature.

Parameters:

  • data (String) —

    message digest to be signed.

Returns:

  • (String) —

    compact signature with binary format.



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# File 'lib/bitcoin/key.rb', line 135

def sign_compact(data)
  signature, rec = secp256k1_module.sign_compact(data, priv_key)
  rec = Bitcoin::Key::COMPACT_SIG_HEADER_BYTE + rec + (compressed? ? 4 : 0)
  [rec].pack('C') + ECDSA::Format::IntegerOctetString.encode(signature.r, 32) +
    ECDSA::Format::IntegerOctetString.encode(signature.s, 32)
end

#to_nested_p2wpkh ⇒ Object

Deprecated.

get p2wpkh address nested in p2sh.



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# File 'lib/bitcoin/key.rb', line 196

def to_nested_p2wpkh
  Bitcoin::Script.to_p2wpkh(hash160).to_p2sh.to_addr
end

#to_p2pkh ⇒ Object

Deprecated.

get pay to pubkey hash address



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# File 'lib/bitcoin/key.rb', line 184

def to_p2pkh
  Bitcoin::Script.to_p2pkh(hash160).to_addr
end

#to_p2wpkh ⇒ Object

Deprecated.

get pay to witness pubkey hash address



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# File 'lib/bitcoin/key.rb', line 190

def to_p2wpkh
  Bitcoin::Script.to_p2wpkh(hash160).to_addr
end

#to_point ⇒ ECDSA::Point

generate pubkey ec point

Returns:



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# File 'lib/bitcoin/key.rb', line 206

def to_point
  p = pubkey
  p ||= generate_pubkey(priv_key, compressed: compressed?)
  ECDSA::Format::PointOctetString.decode(p.htb, Bitcoin::Secp256k1::GROUP)
end

#to_wif ⇒ Object

export private key with wif format



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# File 'lib/bitcoin/key.rb', line 98

def to_wif
  version = Bitcoin.chain_params.privkey_version
  hex = version + priv_key
  hex += '01' if compressed?
  hex += Bitcoin.calc_checksum(hex)
  Base58.encode(hex)
end

#verify(sig, data, algo: :ecdsa) ⇒ Boolean

verify signature using public key

Parameters:

  • sig (String) —

    signature data with binary format

  • data (String) —

    original message

  • algo (Symbol) (defaults to: :ecdsa) —

    signature algorithm. ecdsa(default) or schnorr.

Returns:

  • (Boolean) —

    verify result



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# File 'lib/bitcoin/key.rb', line 160

def verify(sig, data, algo: :ecdsa)
  return false unless valid_pubkey?
  begin
    case algo
    when :ecdsa
      sig = ecdsa_signature_parse_der_lax(sig)
      secp256k1_module.verify_sig(data, sig, pubkey)
    when :schnorr
      secp256k1_module.verify_sig(data, sig, xonly_pubkey, algo: :schnorr)
    else
      false
    end
  rescue Exception
    false
  end
end

#xonly_pubkey ⇒ String

get xonly public key (32 bytes).

Returns:

  • (String) —

    xonly public key with hex format



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# File 'lib/bitcoin/key.rb', line 214

def xonly_pubkey
  pubkey[2..65]
end