text: #!/usr/bin/env python3
  # Copyright (c) 2015-2018 The BitSilver Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  from argparse import ArgumentParser
  from base64 import urlsafe_b64encode
  from binascii import hexlify
  from getpass import getpass
  from os import urandom
  
  import hmac
  
  def generate_salt(size):
      """Create size byte hex salt"""
      return hexlify(urandom(size)).decode()
  
  def generate_password():
      """Create 32 byte b64 password"""
      return urlsafe_b64encode(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():
      parser = ArgumentParser(description='Create login credentials for a JSON-RPC user')
      parser.add_argument('username', help='the username for authentication')
      parser.add_argument('password', help='leave empty to generate a random password or specify "-" to prompt for password', nargs='?')
      args = parser.parse_args()
  
      if not args.password:
          args.password = generate_password()
      elif args.password == '-':
          args.password = getpass()
  
      # Create 16 byte hex salt
      salt = generate_salt(16)
      password_hmac = password_to_hmac(salt, args.password)
  
      print('String to be appended to bitsilver.conf:')
      print('rpcauth={0}:{1}${2}'.format(args.username, salt, password_hmac))
      print('Your password:\n{0}'.format(args.password))
  
  if __name__ == '__main__':
      main()
  