ksydfius's Ksydfius Encryption
| Download ksydfius5.zip, 25 kb (password: crackmes.de) Browse contents of ksydfius5.zip Read the readme :) that should be enough to get you started...
Difficulty: 4 - Needs special knowledge | RatingWaiting for at least 3 votes View profile of ksydfius » |
Solutions
There are no solutions to this crackme yet. Have you solved it? Please write a tutorial and submit it here!
Discussion and comments
| ksydfius Author 20. Oct 2012 | anybody working on this? |
|---|---|
| mausy131 20. Oct 2012 | Well i don't know anything about encryption. Still new to reverse engineering :) |
| redoC 08. May 2015 | Has this one real solution? Here is encryption in C-code: //////////////////////////////////////////////////////// char* Encrypt (char *plaintext, char *key) { unsigned char bit_shift; int i, index = 0; for (i = 0; i < strlen(key); i++) index += key[i]; index = index % 32; for (i = 0; i < strlen(plaintext); i++) { plaintext[i] += key[index]; bit_shift = key[index] % 8; if ((plaintext[i] % 2) == 0) { plaintext[i] = (BYTE(plaintext[i]) >> bit_shift) | (BYTE(plaintext[i]) << (8 - bit_shift)); // bit swap index = BYTE(plaintext[i]) % 32; } else { plaintext[i] = (BYTE(plaintext[i]) << bit_shift) | (BYTE(plaintext[i]) >> (8 - bit_shift)); // bit swap index = BYTE(plaintext[i]) % 32; plaintext[i] += 1; } } return plaintext; } //////////////////////////////////////////////////////// Crackme is bit confusing because this is more hash function than cipher. There's no straightforward decryption algo because even with known key there's ambiguity decision which bit swap to use. Also if we look at algo, ciphertext should not contain any zero bytes!? ...anybody working on this? |
You may leave your comment, thoughts and discuss this crackme with other reversers here.
Acting childish will not be tolerated.
HTML and such will be left as-is, so don't try.