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  1. import sys
  2.  
  3. #Suppose you are told that the one time pad 
  4. #encryption of the message "attack at dawn" 
  5. #is 6c73d5240a948c86981bc294814d 
  6. #(the plaintext letters are encoded 
  7. #    as 8-bit ASCII and the given ciphertext
  8. # is written in hex). What would be the one 
  9. #time pad encryption of the message "attack 
  10. #at dusk" under the same OTP key?
  11.  
  12.  
  13. #MSGS = ( ---  11 secret messages  --- )
  14.  
  15. def strxor(a, b):     # xor two strings of different lengths
  16.     if len(a) > len(b):
  17.         return "".join([chr(ord(x) ^ ord(y)) for (x, y) in zip(a[:len(b)], b)])
  18.     else:
  19.         return "".join([chr(ord(x) ^ ord(y)) for (x, y) in zip(a, b[:len(a)])])
  20.  
  21. def random(size=16):
  22.     return open("/dev/urandom").read(size)
  23.  
  24. def encrypt(key, msg):
  25.     c = strxor(key, msg)
  26.     print
  27.     print c.encode('hex')
  28.     return c
  29.  
  30. def printAscii(msg):
  31.     z = [chr(ord(x)) for x in msg] 
  32.     x = "".join(z)
  33.     print x.encode('hex')
  34.  
  35. def main():
  36.     text = "attack at dawn"
  37.  
  38.  
  39.     enc = "6c73d5240a948c86981bc294814d".decode('hex')
  40.     key = strxor(text, enc)
  41.  
  42.  
  43.     text2 = "attack at dusk"
  44.     enc2 = strxor(text2, key)
  45.  
  46.     print enc2.encode('hex')
  47.  
  48.  
  49.  
  50. main()
Success #stdin #stdout 0.01s 7220KB
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6c73d5240a948c86981bc2808548
https://ideone.com/8ujpLK
language:
Python (cpython 2.7.16)
created:
2 days ago
visibility:
public

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