Sure thing. Think of the brain like a super‑sized, highly volatile database. The best “firewall” is a mix of isolation and encryption. You isolate the critical circuits—like sandboxing a VM—so that external code can’t touch them. Then you encrypt all signals, so even if somebody taps the wire, they get scrambled data. Add a zero‑trust model: every input and output is authenticated and audited, and the system only runs what it explicitly knows is safe. In practice that means implanting secure, tamper‑evident chips and constantly monitoring for anomalies. It’s slow, heavy, and you’ll need a lot of trust in the hardware, but it’s the closest you get to a biological firewall.