The File Key is symmetric, but the header having recipient implies this is public key crypto. So break the public key crypto (e.g. X25519), and you don't need

The File Key is symmetric, but the header having recipient implies this is public key crypto. So break the public key crypto (e.g. X25519), and you don't need to crack the symmetric key. Also 128 bit? That's not quantum safe either, thanks to Grover's algorithm.