rev02

rev_kids20

Task: 64-bit non-stripped PIE ELF that asks for train-route fields, concatenates them into an RC4 key, and decrypts a flag appended to its own file. Solution: extract the expected field values from each check_*_0 validator, recover the no-separator concatenation order, then run custom RC4 (KSA prepare_key + PRGA rc4) over the 44-byte tail ciphertext (offset filesize-4-44).