9.3 Millenium game save file.
rt=rt+"T"
else:
rt=rt+"F"
print rt
Sample:...TTTFTFTTTFFFTTTFTTTTTTFTTFFTTTFTFTTFTTFFFFFF....
Entropy is very close to 1 (i.e., 1 bit per byte).
Let’s generate random decimal digits:
#!/usr/bin/env python
import random, sys
rt=""
for i in range(102400):
rt=rt+"%d" % random.randint(0,9)
print rt
Sample:...52203466119390328807552582367031963888032....
Entropy will be close to 3.32, indeed, this islog 2 (10).
9.2.9 Making lower level of entropy
The author of these lines once saw a software which stored each byte of encrypted data in 3 bytes: each
has≈
byte
3 value, soreconstructingencryptedbytebackinvolvingsummingup3consecutivebytes. Looks
absurdly.
But some people say this was done in order to conceal the very fact the data has something encrypted
inside: measuring entropy of such block will show much lower level of it.
9.3 Millenium game save file
The “Millenium Return to Earth” is an ancient DOS game (1991), that allows you to mine resources, build
ships, equip them and send them on other planets, and so on^11.
Like many other games, it allows you to save all game state into a file.
Let’s see if we can find something in it.
(^11) It can be downloaded for freehere