#!/usr/bin/env python
#
# /* RC4 - Stream Cipher Algorithm/Source Code */

import sys, os, struct

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


#-----------------------------------------
# 
# echo "Protected Privacy" | python ./rc4__STDIN.py "SecretKeyWord"
# 
# 	Keyword    = SecretKeyWord
# 		(hex)    = 53:65:63:72:65:74:4B:65:79:57:6F:72:64
# 	
# 	Plaintext  = 50:72:6F:74:65:63:74:65:64:20:50:72:69:76:61:63:79:0A
# 	Keystream  = ED:FD:04:87:9D:65:25:3C:9F:45:51:7F:93:2C:77:A9:3C:26
# 	Ciphertext = BD:8F:6B:F3:F8:06:51:59:FB:65:01:0D:FA:5A:16:CA:45:2C
#
import rc4_algorithm as rc4  # rc4_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
  #  
  n = c = int(0)

  if (len(sys.argv) == 2):
    for i in range(len(sys.argv[1])): rc4.KeyWord[i] = ord(sys.argv[1][i])
    rc4.KeyLen = len(sys.argv[1])
  

  # -----------------------------------------
  # Initialisation of rc4
  # 
  # perform the Key Schedule
  rc4.KSA()


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

  Keystream = ''

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

    outB = rc4.PRGA()
    Keystream += ('%02X:' % outB)

  printf ('%s' % Keystream[0:-1])


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