title: All Possible combination for an HEX Value from a given set of chars
body: <p>I am new to python and programming,</p>
  
  <p>I am looking for a code, or a sample code that can have a predefined set of hex values 
  and that can find the 3 used values within to generate a certain value.</p>
  
  <p>lets say I have a value of : 0x50158A51</p>
  
  <p>this is a 4 byte (32 bit) hex value</p>
  
  <p>now i need to find the values which when added or subtracted (from the provided set)  will end with this result.</p>
  
  <p>for example:</p>
  
  <p>0x75612171 + 0x75612171 + 0x6553476F = 0x50158A51 </p>
  
  <ul>
  <li>notice that the values added are all from the allowed set</li>
  </ul>
  
  <p>Just to be clear i have a limited chars set</p>
  
  <p>which is :</p>
  
  <pre><code>\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13
  \x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\x20\x21\x22\x23\x24\x25\x26
  \x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39
  \x3a\x3b\x3c\x3d\x3e\x3f\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c
  \x4d\x4e\x4f\x50\x51\x52\x53\x54\x55\x56\x57\x58\x59\x5a\x5b\x5c\x5d\x5e\x5f
  \x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f\x70\x71\x72
  \x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f\x80\x81\x82\x83\x84\x85
  \x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98
  \x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab
  \xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe
  \xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1 
  \xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4 
  \xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7 
  \xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff
  </code></pre>
  
  <p>i used a simple code to calculate 3 values:</p>
  
  <pre><code>#!/usr/bin/python
  
  hex1 = 0x55555521
  hex2 = 0x55555421
  hex3 = 0x6D556F49
  
  calc = hex1 + hex2 + hex3
  print hex(calc)
  </code></pre>
  
  <p>which will give a result of:</p>
  
  <pre><code>root@linux:~# ./calc2.py
  0x150158a51
  </code></pre>
  
  <p>i need to some how reverse the process of the answer by placing variations from my allowed set into the variables</p>
  
  <p>for example:</p>
  
  <p>placing 4 byte hex values from the set into the variables</p>
  
  <pre><code> try: 
  
  hex1 = placing 4bytes from allowed set
  hex2 = placing 4bytes from allowed set
  hex3 = placing 4bytes from allowed set
  
  if result (hex1+hex2+hex3)  = 0x150158a51
  then
  print "values used for this results are: hex1 hex2 hex3"
  </code></pre>
  
  <p>Thank you in advance.</p>