rev12

rev_kids20

Task: 64-bit non-stripped PIE ELF in the train/path/station self-decrypting custom-RC4 family (sibling of RE4_rev02) but with many more struct fields (driver, passport, country, dates, durations). Solution: reverse every check_*_0 validator to extract expected constants, concatenate all field values in entry order (no separator) as the RC4 key, then let the binary read its own appended 50-byte ciphertext (at filesize-4-50) and decrypt the flag.