Class: Derivator::Mnemonic

Inherits:
Object
  • Object
show all
Defined in:
lib/derivator/mnemonic.rb

Overview

BIP39 mnemonic generation.

Constant Summary collapse

WORDS =

Word list (ordered). Only English is supported.

File.readlines(__dir__ + '/word_lists/english.txt', chomp: true)
SEED_ITERATIONS = 
2048
SEED_KEY_LENGTH = 
64

Class Method Summary collapse

Class Method Details

.generate(bytes = random_bytes) ⇒ String

Generates mnemonic.

Parameters:

  • bytes (String) (defaults to: random_bytes) —

    bytes to generate mnemonic from

Returns:

  • (String) —

    mnemonic (12 words)



22
23
24
25
26
27
28
29
30
31
32
 
# File 'lib/derivator/mnemonic.rb', line 22

def generate(bytes = random_bytes)
  checksum = OpenSSL::Digest::SHA256.new(bytes).digest[0..0]
  checksum_bits = checksum[0..0].unpack('B4').first # first 4 bits
  bits = bytes.unpack('B*').first + checksum_bits
  mnemonic = bits.chars.
    each_slice(11).
    map(&:join).
    map { |x| x.to_i(2) }.
    map { |x| WORDS[x] }.
    join(' ')
end

.random_bytes ⇒ String

Generates 128 bits of random

Returns:

  • (String) —

    16 random bytes



14
15
16
 
# File 'lib/derivator/mnemonic.rb', line 14

def random_bytes
  SecureRandom.random_bytes(128 / 8) # 128 bits
end

.seed(mnemonic, password = '') ⇒ Object

Generates master seed.

Parameters:

  • mnemonic (String) —

    mnemonic (12 words) to generate seed from

  • password (String) (defaults to: '') —

    password



38
39
40
41
42
43
44
45
46
47
48
 
# File 'lib/derivator/mnemonic.rb', line 38

def seed(mnemonic, password = '')
  salt = "mnemonic#{password}"
  result_bytes = OpenSSL::KDF.pbkdf2_hmac(
    mnemonic,
    salt: salt,
    iterations: SEED_ITERATIONS,
    length: SEED_KEY_LENGTH,
    hash: 'SHA512'
  )
  result_bytes.unpack('H*').first
end