All Writeups

Comprehensive collection of CTF challenges, solutions, and insights.

Exploiting a weak (low) DSA nonce k to brute-force the signing secret, recover the private key x, and derive the flag via SHA-256.

Reconstructing a truncated RSA private exponent via brute force over the missing 4 hex digits, then using it to decrypt a raw RSA ciphertext.

Identifying hex-encoded XOR ciphertext and brute-forcing the single-byte key using a known-plaintext crib from the flag format.