Digital Forensics:Decode Cipher ----write up of 'cm08' for in Cyber FastTrack


Problem: decode the cipher in a text file.

Tools: ihex, python, sublime

Solution: 

Step 1: open the file 

It' s a text file. When I open it, I found that there are some invisible characters on it.


Step 2: open it as ihex

Then I open it with ihex,  I found it's wired that there were 'C3' s in it.

Step 3: find the trick in it.


Then I copied the characters and removed all the 'C3' s.

86 AC A1 A7 C2 BA 8D A1 B3 B4 A5 B2 9F 8F A6 9F 93 B7 A9 B4 A3 A8 A9 AE A7 9F 82 A9 B4 B3 0A 

 I found the difference between 'A1' and 'A7'  was 6, then I thought they might be 'a' and 'g' in word 'flag'. 

 Then I changed the offset as 64 in order to print 'A1' to '97' which is ASCII code of 'a' and printed all of them.

Flag?zMaster_Of_Switching_Bits







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