Topic created on: April 21, 2007 11:34 CDT by
spx2 
.
hello
i would like to ask about some papers on common encryption schemes that found comprehensible they would help me on solving some crackmes
thanks
SHA-1, SHA-256, CRC-16 and -32 (not really crypto, but...), AES, RC4, <xyz>fish, ... The list is endless, and the more you learn, the more you'll recognize when you see it in a disassembler.
I once reversed RC4 and wrote an IDC script to decrypt the code, and didn't know it was RC4 at the time. I learned a year or so later that it was RC4 -- didn't matter for my goal (decrypting the code). How much you need to learn will vary based on your goals.
If you want to write the world's best solution to a crackme, you might need to learn a lot of crypto algorithms until you find the one used in that particular crackme. Without that knowledge, your paper would say, "It does crypto". With that knowledge, you can look like a genius by saying, "It does AES-CBC followed by a round of RC4, using the MD5 hash of the first-stage decrypt as the IV." ;-)
Disclaimer: I'm no crypto expert, so forgive me if my "genius solution" is technically inaccurate. :(
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