#!/usr/bin/python3

"""
* File     : pcp2-check-pubkey 
* [Part of the Pure Crypto Project https://senderek.ie/pcp2]
*
* Version  : 2.0
* Date     : 6 Jan 2025
* License  : BSD
*
* Copyright (c) 2003 - 2025
*	Ralf Senderek, Ireland.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*	   This product includes software developed by Ralf Senderek.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
"""


import sys, os

# default intallation path for pcp2 modules
sys.path.append("/usr/share/pcp2")
import pure 

ERR_CORRUPT = 4

#-----------------------------------------------------------#
def key_valid(K):
     # returns K if valid, else None.
     if len(K) == 6 :
          StoredSecHash = pure.toLong(K[5][15:])
          print(StoredSecHash)
          
          pure.Modulus = pure.toLong(K[0])
          pure.Encryption = pure.toLong(K[1])
          pure.HashModulus = pure.toLong(K[2])
          pure.Generator = pure.toLong(K[3])
          pure.UserID = pure.Line(K[4])
          # check the integrity of the stored securityhash
          pure.print_securityhash(False)
          print(pure.Securityhash)
          if StoredSecHash != pure.Securityhash :
               print ("\nWarning: The key material", end="") 
               print (" is inconsistent with the stored Security-Hash.")
               print ("Your key has been tampered with !.\n")
               sys.exit(ERR_CORRUPT)
          else:
               print ("The integrity for [", KeyfileName ,"] is checked successfully!")
               return K 
     else :
          print ("The public key is corrupted.")
     return None

#-----------------------------------------------------------#

if len(sys.argv) == 2:
     print()

     try:
          FILE = open(sys.argv[1], "rb")
          Content = FILE.readlines()
          FILE.close()
          KeyfileName = sys.argv[1]
          Result = key_valid (Content)
     except IOError :
          print ("\nCannot read the public key", sys.argv[1])
          sys.exit(1)

else:
     print("usage: pcp2-check-pubkey publickeyfile")

sys.exit(0)

#-----------------------------------------------------------#
#      Copyright 2003 - 2025, Ralf Senderek, Ireland        #
#-----------------------------------------------------------#