text: #!/usr/bin/env python3
  # Copyright (c) 2015-2017 The Bitcoin Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  import sys
  import os
  from random import SystemRandom
  import base64
  import hmac
  
  def generate_salt():
      # This uses os.urandom() underneath
      cryptogen = SystemRandom()
  
      # Create 16 byte hex salt
      salt_sequence = [cryptogen.randrange(256) for _ in range(16)]
      return ''.join([format(r, 'x') for r in salt_sequence])
  
  def generate_password():
      """Create 32 byte b64 password"""
      return base64.urlsafe_b64encode(os.urandom(32)).decode('utf-8')
  
  def password_to_hmac(salt, password):
      m = hmac.new(bytearray(salt, 'utf-8'), bytearray(password, 'utf-8'), 'SHA256')
      return m.hexdigest()
  
  def main():
      if len(sys.argv) < 2:
          sys.stderr.write('Please include username (and an optional password, will generate one if not provided) as an argument.\n')
          sys.exit(0)
  
      username = sys.argv[1]
  
      salt = generate_salt()
      if len(sys.argv) > 2:
          password = sys.argv[2]
      else:
          password = generate_password()
      password_hmac = password_to_hmac(salt, password)
  
      print('String to be appended to bitcoin.conf:')
      print('rpcauth={0}:{1}${2}'.format(username, salt, password_hmac))
      print('Your password:\n{0}'.format(password))
  
  if __name__ == '__main__':
      main()
  