Module: Tapyrus::Secp256k1::RFC6979

Defined in:
lib/tapyrus/secp256k1/rfc6979.rb

Constant Summary collapse

INITIAL_V = 
"0101010101010101010101010101010101010101010101010101010101010101".htb
INITIAL_K = 
"0000000000000000000000000000000000000000000000000000000000000000".htb
ZERO_B = 
"00".htb
ONE_B = 
"01".htb

Class Method Summary collapse

Class Method Details

.generate_rfc6979_nonce(key_data, extra_entropy) ⇒ Integer

generate temporary key k to be used when ECDSA sign. tools.ietf.org/html/rfc6979#section-3.2

Parameters:

  • key_data (String) —

    a data contains private key and message.

  • extra_entropy (String) —

    extra entropy with binary format.

Returns:



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# File 'lib/tapyrus/secp256k1/rfc6979.rb', line 16

def generate_rfc6979_nonce(key_data, extra_entropy)
  v = INITIAL_V # 3.2.b
  k = INITIAL_K # 3.2.c

  # 3.2.d
  k = Tapyrus.hmac_sha256(k, v + ZERO_B + key_data + extra_entropy)

  # 3.2.e
  v = Tapyrus.hmac_sha256(k, v)

  # 3.2.f
  k = Tapyrus.hmac_sha256(k, v + ONE_B + key_data + extra_entropy)

  # 3.2.g
  v = Tapyrus.hmac_sha256(k, v)

  # 3.2.h
  t = ""
  10_000.times do
    v = Tapyrus.hmac_sha256(k, v)
    t = (t + v)
    t_num = t.bth.to_i(16)
    return t_num if 1 <= t_num && t_num < Tapyrus::Secp256k1::GROUP.order
    k = Tapyrus.hmac_sha256(k, v + "00".htb)
    v = Tapyrus.hmac_sha256(k, v)
  end
  raise "A valid nonce was not found."
end