I am trying to find an already written or available tool that can help Bruteforce CBC with unknown Key and Unknown IV. I have looked over Hashcat and JTR to no avail, I also would love to know how one goes about knowing they are looking at DES from the byte level versus says 3DES or AES? Any help appreciated. Thanks.

closed as off-topic by kelalaka, Maarten Bodewes, e-sushi Dec 3 at 9:09

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  • "Programming questions are off-topic even if you are writing or debugging cryptographic code. Unless your question is specifically about how the cryptographic algorithm, protocol or side-channel (mitigation) works, you should look into asking on Stack Overflow instead." – kelalaka, e-sushi
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  • is this a CTF. How many blocks you have? You cannot distinguish by looking at the ciphertext. Ciphertexts of AES differs from DES only by the block size. Bruteforce for DES can be achievable by some institutions, 3DES and AES-128 is infeasible, yet. – kelalaka Nov 27 at 21:20
  • No this is not a CTF, I find a lot of DES used in webapps to hide data encoded in base64. I would like to leverage this to show vulnerabilies. However, I have never done much with binary based DES. I am trying to create a POC in python. POC: Read in DES CBC Binary File Convert to HEX – pent3st3r Nov 27 at 21:50
  • Probably they know it too or they don't care. programming questions are off-topic here. – kelalaka Nov 27 at 21:54
  • Fair enough, let me ask, how does one manually decrypt DES CBC not knowing the IV? – pent3st3r Nov 27 at 21:57
  • 1
    manually? If you look at the wikipedia for modes of operations, you will see that lack of IV will only effect two blocks. – kelalaka Nov 27 at 22:00

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