Class: Bitcoin::Key

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

Overview

Elliptic Curve key as used in bitcoin.

Constant Summary collapse

MIN_PRIV_KEY_MOD_ORDER = 
0x01
MAX_PRIV_KEY_MOD_ORDER =

Order of secp256k1’s generator minus 1.

0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364140

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(privkey = nil, pubkey = nil, opts = {compressed: true}) ⇒ Key

Create a new key with given privkey and pubkey.

Bitcoin::Key.new
Bitcoin::Key.new(privkey)
Bitcoin::Key.new(nil, pubkey)



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# File 'lib/bitcoin/key.rb', line 41

def initialize(privkey = nil, pubkey = nil, opts={compressed: true})
  compressed = opts.is_a?(Hash) ? opts.fetch(:compressed, true) : opts
  @key = Bitcoin.bitcoin_elliptic_curve
  @pubkey_compressed = pubkey ? self.class.is_compressed_pubkey?(pubkey) : compressed
  set_priv(privkey)  if privkey
  set_pub(pubkey, @pubkey_compressed)  if pubkey
end

Instance Attribute Details

#key ⇒ Object (readonly)

Returns the value of attribute key.



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# File 'lib/bitcoin/key.rb', line 8

def key
  @key
end

Class Method Details

.from_base58(str) ⇒ Object

Import private key from base58 fromat as described in en.bitcoin.it/wiki/Private_key#Base_58_Wallet_Import_format and en.bitcoin.it/wiki/Base58Check_encoding#Encoding_a_private_key. See also #to_base58



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# File 'lib/bitcoin/key.rb', line 24

def self.from_base58(str)
  hex = Bitcoin.decode_base58(str)
  compressed = hex.size == 76
  version, key, flag, checksum = hex.unpack("a2a64a#{compressed ? 2 : 0}a8")
  raise "Invalid version"   unless version == Bitcoin.network[:privkey_version]
  raise "Invalid checksum"  unless Bitcoin.checksum(version + key + flag) == checksum
  key = new(key, nil, compressed)
end

.from_bip38(encrypted_privkey, passphrase) ⇒ Object

Import private key from bip38 (non-ec-multiply) fromat as described in github.com/bitcoin/bips/blob/master/bip-0038.mediawiki See also #to_bip38



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

def self.from_bip38(encrypted_privkey, passphrase)
  version, flagbyte, addresshash, encryptedhalf1, encryptedhalf2, checksum =
    [ Bitcoin.decode_base58(encrypted_privkey) ].pack("H*").unpack("a2aa4a16a16a4")
  compressed = (flagbyte == "\xe0") ? true : false

  raise "Invalid version"   unless version == "\x01\x42"
  raise "Invalid checksum"  unless Digest::SHA256.digest(Digest::SHA256.digest(version + flagbyte + addresshash + encryptedhalf1 + encryptedhalf2))[0...4] == checksum

  require 'scrypt' unless defined?(::SCrypt::Engine)
  buf = SCrypt::Engine.__sc_crypt(passphrase, addresshash, 16384, 8, 8, 64)
  derivedhalf1, derivedhalf2 = buf[0...32], buf[32..-1]

  aes = proc{|k,a|
    cipher = OpenSSL::Cipher::AES.new(256, :ECB); cipher.decrypt; cipher.padding = 0; cipher.key = k
    cipher.update(a)
  }

  decryptedhalf2 = aes.call(derivedhalf2, encryptedhalf2)
  decryptedhalf1 = aes.call(derivedhalf2, encryptedhalf1)

  priv = decryptedhalf1 + decryptedhalf2
  priv = (priv.unpack("H*")[0].to_i(16) ^ derivedhalf1.unpack("H*")[0].to_i(16)).to_s(16).rjust(64, '0')
  key = Bitcoin::Key.new(priv, nil, compressed)

  if Digest::SHA256.digest( Digest::SHA256.digest( key.addr ) )[0...4] != addresshash
    raise "Invalid addresshash! Password is likely incorrect."
  end

  key
end

.from_warp(passphrase, salt = "", compressed = false) ⇒ Object

Import private key from warp fromat as described in github.com/keybase/warpwallet keybase.io/warp/



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

def self.from_warp(passphrase, salt="", compressed=false)
  require 'scrypt' unless defined?(::SCrypt::Engine)
  s1 = SCrypt::Engine.scrypt(passphrase+"\x01", salt+"\x01", 2**18, 8, 1, 32)
  s2 = OpenSSL::PKCS5.pbkdf2_hmac(passphrase+"\x02", salt+"\x02", 2**16, 32, OpenSSL::Digest::SHA256.new)
  s3 = s1.bytes.zip(s2.bytes).map{|a,b| a ^ b }.pack("C*")

  key = Bitcoin::Key.new(s3.unpack("H*")[0], nil, compressed)
  # [key.addr, key.to_base58, [s1,s2,s3].map{|i| i.unpack("H*")[0] }, compressed]
  key
end

.generate(opts = {compressed: true}) ⇒ Object

Generate a new keypair.

Bitcoin::Key.generate



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

def self.generate(opts={compressed: true})
  k = new(nil, nil, opts); k.generate; k
end

.recover_compact_signature_to_key(data, signature_base64) ⇒ Object

Thanks to whoever wrote pastebin.com/bQtdDzHx for help with compact signatures

Given data and a compact signature (65 bytes, base64-encoded to a larger string), recover the public components of the key whose private counterpart validly signed data.

If the signature validly signed data, create a new Key having the signing public key and address. Otherwise return nil.

Be sure to check that the returned Key matches the one you were expecting! Otherwise you are merely checking that someone validly signed the data.



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# File 'lib/bitcoin/key.rb', line 152

def self.recover_compact_signature_to_key(data, signature_base64)
  signature = signature_base64.unpack("m0")[0]
  return nil if signature.size != 65

  version = signature.unpack('C')[0]
  return nil if version < 27 or version > 34
 
  compressed = (version >= 31) ? (version -= 4; true) : false

  hash = Bitcoin.bitcoin_signed_message_hash(data)
  pub_hex = Bitcoin::OpenSSL_EC.recover_public_key_from_signature(hash, signature, version-27, compressed)
  return nil unless pub_hex

  Key.new(nil, pub_hex)
end

.verify_message(address, signature, message) ⇒ Object 



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

def self.verify_message(address, signature, message)
  Bitcoin.verify_message(address, signature, message)
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/bitcoin/key.rb', line 33

def ==(other)
  self.priv == other.priv
end

#addr ⇒ Object

Get the address corresponding to the public key.



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# File 'lib/bitcoin/key.rb', line 102

def addr
  Bitcoin.hash160_to_address(hash160)
end

#compressed ⇒ Object 



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# File 'lib/bitcoin/key.rb', line 87

def compressed
  @pubkey_compressed
end

#generate ⇒ Object

Generate new priv/pub key.



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# File 'lib/bitcoin/key.rb', line 50

def generate
  @key.generate_key
end

#hash160 ⇒ Object

Get the hash160 of the public key.



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# File 'lib/bitcoin/key.rb', line 97

def hash160
  Bitcoin.hash160(pub)
end

#priv ⇒ Object

Get the private key (in hex).



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# File 'lib/bitcoin/key.rb', line 55

def priv
  return nil  unless @key.private_key
  @key.private_key.to_hex.rjust(64, '0')
end

#priv=(priv) ⇒ Object

Set the private key to priv (in hex).



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# File 'lib/bitcoin/key.rb', line 61

def priv= priv
  set_priv(priv)
  regenerate_pubkey
end

#pub ⇒ Object

Get the public key (in hex). In case the key was initialized with only a private key, the public key is regenerated.



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# File 'lib/bitcoin/key.rb', line 69

def pub
  regenerate_pubkey unless @key.public_key
  return nil        unless @key.public_key
  @pubkey_compressed ? pub_compressed : pub_uncompressed
end

#pub=(pub) ⇒ Object

Set the public key (in hex).



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

def pub= pub
  set_pub(pub)
end

#pub_compressed ⇒ Object 



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# File 'lib/bitcoin/key.rb', line 75

def pub_compressed
  public_key = @key.public_key
  public_key.group.point_conversion_form = :compressed
  public_key.to_hex.rjust(66, '0')
end

#pub_uncompressed ⇒ Object 



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# File 'lib/bitcoin/key.rb', line 81

def pub_uncompressed
  public_key = @key.public_key
  public_key.group.point_conversion_form = :uncompressed
  public_key.to_hex.rjust(130, '0')
end

#sign(data) ⇒ Object

Sign data with the key.

key1 = Bitcoin::Key.generate
sig = key1.sign("some data")



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# File 'lib/bitcoin/key.rb', line 109

def sign(data)
  Bitcoin.sign_data(key, data)
end

#sign_message(message) ⇒ Object 



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# File 'lib/bitcoin/key.rb', line 127

def sign_message(message)
  Bitcoin.sign_message(priv, pub, message)['signature']
end

#to_base58 ⇒ Object

Export private key to base58 format. See also Key.from_base58



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# File 'lib/bitcoin/key.rb', line 170

def to_base58
  data = Bitcoin.network[:privkey_version] + priv
  data += "01"  if @pubkey_compressed
  hex  = data + Bitcoin.checksum(data)
  Bitcoin.int_to_base58( hex.to_i(16) )
end

#to_bip38(passphrase) ⇒ Object

Export private key to bip38 (non-ec-multiply) format as described in github.com/bitcoin/bips/blob/master/bip-0038.mediawiki See also Key.from_bip38



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# File 'lib/bitcoin/key.rb', line 181

def to_bip38(passphrase)
  flagbyte = compressed ? "\xe0" : "\xc0"
  addresshash = Digest::SHA256.digest( Digest::SHA256.digest( self.addr ) )[0...4]

  require 'scrypt' unless defined?(::SCrypt::Engine)
  buf = SCrypt::Engine.__sc_crypt(passphrase, addresshash, 16384, 8, 8, 64)
  derivedhalf1, derivedhalf2 = buf[0...32], buf[32..-1]

  aes = proc{|k,a,b|
    cipher = OpenSSL::Cipher::AES.new(256, :ECB); cipher.encrypt; cipher.padding = 0; cipher.key = k
    cipher.update [ (a.to_i(16) ^ b.unpack("H*")[0].to_i(16)).to_s(16).rjust(32, '0') ].pack("H*")
  }

  encryptedhalf1 = aes.call(derivedhalf2, self.priv[0...32], derivedhalf1[0...16])
  encryptedhalf2 = aes.call(derivedhalf2, self.priv[32..-1], derivedhalf1[16..-1])

  encrypted_privkey = "\x01\x42" + flagbyte + addresshash + encryptedhalf1 + encryptedhalf2
  encrypted_privkey += Digest::SHA256.digest( Digest::SHA256.digest( encrypted_privkey ) )[0...4]

  encrypted_privkey = Bitcoin.encode_base58( encrypted_privkey.unpack("H*")[0] )
end

#verify(data, sig) ⇒ Object

Verify signature sig for data.

key2 = Bitcoin::Key.new(nil, key1.pub)
key2.verify("some data", sig)



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# File 'lib/bitcoin/key.rb', line 116

def verify(data, sig)
  regenerate_pubkey unless @key.public_key
  sig = Bitcoin::OpenSSL_EC.repack_der_signature(sig)
  if sig
    @key.dsa_verify_asn1(data, sig)
  else
    false
  end
end

#verify_message(signature, message) ⇒ Object 



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# File 'lib/bitcoin/key.rb', line 131

def verify_message(signature, message)
  Bitcoin.verify_message(addr, signature, message)
end