crypto writeups
find crypto ctf writeups.
crypto writeups show the math behind the solve — which RSA property was broken, why an AES mode leaked, or how a custom cipher fell. read them to learn the attack patterns that recur across competitions.
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what crypto writeups cover
- RSA — small exponentwriteups show e=3 with a small message solved by a plain cube root, no factoring.
- RSA — common modulus / Wienerwriteups recover the message or private key from a shared modulus or a too-small d.
- AES ECBwriteups exploit identical ciphertext blocks with byte-at-a-time chosen-plaintext attacks.
- CBC padding oraclewriteups decrypt or forge ciphertext byte-by-byte using a padding-validity oracle.
- XOR cipherwriteups recover single-byte keys by frequency scoring and repeating keys via index of coincidence.
- classical ciphersCaesar and Vigenere writeups show brute force and key-length recovery by frequency analysis.
read writeups after you've tried
writeups teach the most when you've already spent real time on a cryptochallenge. if you're stuck mid-solve, get a spoiler-free hint first — then read a writeup to see the gap between your approach and the intended one.