$ cat writeup.md…
$ cat writeup.md…
hackthebox
Task: a custom SecureHash built on a home-rolled SecureCipher (key-dependent S-box, bit permutation, 100 rounds) digests the 32-byte flag; recover it from a single hex digest. Solution: the S-box is affine over GF(2), so the whole cipher collapses to one affine map; with key == plaintext == flag the digest is enc_flag(flag), giving a 256x256 GF(2) linear system solved by Gaussian elimination.
Permission denied (requires tier.pro)
Sign in with GitHub, Discord, or Google to continue. No email required.
$sign in$ grep --similar