#!/usr/bin/env python
#
# /* zx8 (ps) - Stream Cipher Algorithm/Source Code */

# /*
# Copyright (c) 2012, Karl-Uwe Frank
# 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.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
# HOLDER 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.
# 
# #** zx8 (ps) algorithm developed by Karl-Uwe Frank
# */

import sys, os

#-----------------------------------------
# Simulate missing ANSI-C "printf"
#
def printf(*args):
  sys.stdout.write(*args)
  sys.stdout.flush()


#-----------------------------------------
# 
# echo -en "Protected Privacy" | python ./zx8_ps__STDIN.py "SecretKeyWord"
# 
#   Keyword    = SecretKeyWord
#     (hex)    = 53:65:63:72:65:74:4B:65:79:57:6F:72:64
#   
#   Plaintext  = 50:72:6F:74:65:63:74:65:64:20:50:72:69:76:61:63:79
#   Keystream  = 62:F9:D4:31:2F:63:CC:08:E1:6F:22:C6:0F:68:EB:F2:1B
#   Ciphertext = 32:8B:BB:45:4A:00:B8:6D:85:4F:72:B4:66:1E:8A:91:62
#
import zx8_ps_algorithm as zx8  # zx8_ps_algorithm.py


#-----------------------------------------
#
def ShowUsage(ThisName):
  printf ("\nUsage: echo \"Plaintext\" \| %s keyword\n\n" % ThisName)



# -----------------------------------------
# Main 
#
def main():
  #
  # Check if a Prarmeter is passed through
  PrgName = sys.argv[0]

  if (len(sys.argv) < 2):
    ShowUsage(PrgName)
    sys.exit()
  
  # -----------------------------------------
  # Read the Encryption Keyword
  #  
  if (len(sys.argv) == 2):
    for i in range(len(sys.argv[1])): zx8.KeyWord[i] = ord(sys.argv[1][i])
    zx8.KeyLen = len(sys.argv[1])

  if (zx8.KeyLen < 8):
    printf ("\nKeyword must be at least 8 characters long\n")
    sys.exit()
  
  #  Show only if Keyword isn't too long  
  if (zx8.KeyLen < 32):
    printf ("\nKeyword    = %s" % zx8.KeyWord)
    printf ("\n  (hex)    = ")
    for i in range(zx8.KeyLen-1): printf ('%02X:' % zx8.KeyWord[i])
    printf ('%02X\n\n' % zx8.KeyWord[i+1])
    

  # -----------------------------------------
  # Initialisation of zx8 (ps)
  # 
  # perform the Key Schedule
  zx8.KSA()


  inB = outB = int(0) 
  BLOCKSIZE  = 1 # Byte

  Plaintext = Keystream = Ciphertext = ''

  # Encrypt from STDIN
  while (True):
    inB = sys.stdin.read(BLOCKSIZE) # read 1 Byte
    if (inB == ''): break # EOF

    outB = zx8.PRGA()
    Keystream  += ('%02X:' % outB)
    Plaintext  += ('%02X:' % ord(inB))
    Ciphertext += ('%02X:' % (ord(inB) ^ outB))

  printf ('Plaintext  = %s\n'  % Plaintext[0:-1])
  printf ('Keystream  = %s\n'  % Keystream[0:-1])
  printf ('Ciphertext = %s\n\n'% Ciphertext[0:-1])


if __name__ == "__main__":
  main()
  sys.exit()