Module: Bitcoin::Secp256k1::Ruby

Defined in:
lib/block_io/extended_bitcoinrb.rb

Class Method Summary collapse

Class Method Details

.sign_ecdsa(data, privkey, extra_entropy) ⇒ Object 



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# File 'lib/block_io/extended_bitcoinrb.rb', line 36

def sign_ecdsa(data, privkey, extra_entropy)
  privkey = privkey.htb
  private_key = ECDSA::Format::IntegerOctetString.decode(privkey)
  extra_entropy ||= ''
  nonce = RFC6979.generate_rfc6979_nonce(privkey + data, extra_entropy)

  # port form ecdsa gem.
  r_point = GROUP.new_point(nonce)

  point_field = ECDSA::PrimeField.new(GROUP.order)
  r = point_field.mod(r_point.x)
  return nil if r.zero?

  rec = r_point.y & 1
  
  e = ECDSA.normalize_digest(data, GROUP.bit_length)
  s = point_field.mod(point_field.inverse(nonce) * (e + r * private_key))

  # covert to low-s
  if s > (GROUP.order / 2)
    s = GROUP.order - s
    rec = r_point.y & 1
  end
  
  return nil if s.zero?

  signature = ECDSA::Signature.new(r, s).to_der

  # these lines lead to performance issues
  #        public_key = Bitcoin::Key.new(priv_key: privkey.bth, :key_type => Bitcoin::Key::TYPES[:compressed]).pubkey # get rid of the key_type warning
  #        raise 'Creation of signature failed.' unless Bitcoin::Secp256k1::Ruby.verify_sig(data, signature, public_key)
  
  [signature, rec]
end