docs: def customPRF512(key, amac, smac, anonce, snonce):
      """Source https://stackoverflow.com/questions/12018920/"""
      A = b"Pairwise key expansion"
      B = b"".join(sorted([amac, smac]) + sorted([anonce, snonce]))
  
      blen = 64
      i = 0
      R = b''
      while i <= ((blen * 8 + 159) / 160):
          hmacsha1 = hmac.new(key, A + chb(0x00) + B + chb(i), hashlib.sha1)
          i += 1
          R = R + hmacsha1.digest()
      return R[:blen]