Module: Tapyrus::Secp256k1::Ruby

Defined in:
lib/tapyrus/secp256k1/ruby.rb

Overview

secp256 module using ecdsa gem github.com/DavidEGrayson/ruby_ecdsa

Class Method Summary collapse

Class Method Details

.generate_key(compressed: true) ⇒ Object

generate tapyrus key object



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# File 'lib/tapyrus/secp256k1/ruby.rb', line 20

def generate_key(compressed: true)
  privkey, pubkey = generate_key_pair(compressed: compressed)
  Tapyrus::Key.new(priv_key: privkey, pubkey: pubkey, compressed: compressed)
end

.generate_key_pair(compressed: true) ⇒ Object

generate ec private key and public key



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# File 'lib/tapyrus/secp256k1/ruby.rb', line 11

def generate_key_pair(compressed: true)
  private_key = 1 + SecureRandom.random_number(GROUP.order - 1)
  public_key = GROUP.generator.multiply_by_scalar(private_key)
  privkey = ECDSA::Format::IntegerOctetString.encode(private_key, 32)
  pubkey = public_key.to_hex(compressed)
  [privkey.bth, pubkey]
end

.generate_pubkey(privkey, compressed: true) ⇒ Object 



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# File 'lib/tapyrus/secp256k1/ruby.rb', line 25

def generate_pubkey(privkey, compressed: true)
  public_key = ECDSA::Group::Secp256k1.generator.multiply_by_scalar(privkey.to_i(16))
  public_key.to_hex(compressed)
end

.repack_pubkey(pubkey) ⇒ Object

if pubkey is hybrid public key format, it convert uncompressed format. lists.linuxfoundation.org/pipermail/bitcoin-dev/2012-June/001578.html



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# File 'lib/tapyrus/secp256k1/ruby.rb', line 83

def repack_pubkey(pubkey)
  p = pubkey.htb
  case p[0]
    when "\x06", "\x07"
      p[0] = "\x04"
      p
    else
      pubkey.htb
  end
end

.sign_data(data, privkey, extra_entropy) ⇒ String

sign data.

Parameters:

  • data (String) —

    a data to be signed with binary format

  • privkey (String) —

    a private key using sign

Returns:

  • (String) —

    signature data with binary format



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# File 'lib/tapyrus/secp256k1/ruby.rb', line 34

def sign_data(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?

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

  if s > (GROUP.order / 2) # convert low-s
    s = GROUP.order - s
  end

  return nil if s.zero?

  signature = ECDSA::Signature.new(r, s).to_der
  public_key = Tapyrus::Key.new(priv_key: privkey.bth).pubkey
  raise 'Creation of signature failed.' unless Tapyrus::Secp256k1::Ruby.verify_sig(data, signature, public_key)
  signature
end

.verify_sig(digest, sig, pubkey) ⇒ Boolean Also known as: valid_sig?

verify signature using public key

Parameters:

  • digest (String) —

    a SHA-256 message digest with binary format

  • sig (String) —

    a signature for data with binary format

  • pubkey (String) —

    a public key corresponding to the private key used for sign

Returns:

  • (Boolean) —

    verify result



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# File 'lib/tapyrus/secp256k1/ruby.rb', line 67

def verify_sig(digest, sig, pubkey)
  begin
    k = ECDSA::Format::PointOctetString.decode(repack_pubkey(pubkey), GROUP)
    signature = ECDSA::Format::SignatureDerString.decode(sig)
    ECDSA.valid_signature?(k, digest, signature)
  rescue Exception
    false
  end
end