Puzzles for Hackers

README

Solutions to the "Puzzles for Hackers" book by Ivan Skylarov
ISBN10: 1-931769-45-1

Solution.txt

>>> from xorencdec import xorencdec
>>> xorencdec('creature_creature_creature',']VTYJQC]aGC]_PDJ[{RJ[EEMLA')
'>$18>$18>$18>$18>$18>$18>$'
>>> xorencdec('Smith','>$18')
'mIXLV'

xorencdec.py

def xorencdec(a, b, debug=False):
  if debug:
    print a," Length: ",len(a)
    print b," Length: ",len(b)
  
  if len(a) < len(b):
    key,string = a,b
  else:
    key,string = b,a
  
  if debug:
    print "Key: ",key," [",len(key),"]"
    print "String: ",string," [",len(string),"]"
  
  wkey=i=0
  output=''
  
  while i<len(string):
    if wkey == len(key):
      wkey = 0
    if debug:
      print "",key
      print " "*wkey,"^ ",wkey
      print "",string
      print " "*i,"^ ",i
      print key[wkey],"^",string[i]," = ",chr(ord(string[i])^ord(key[wkey]))
    output += chr(ord(string[i])^ord(key[wkey]))
    wkey += 1
    i+=1
  
  return output