He explained with a story:
v → e p → k n → m space y → b h → s t → g w → d y → b space l → o y → b space d → w w → d l → o t → g space a → z l → o k → p w → d y → b t → g vpn yhtwy ly dwlt alkwyt
It seems the phrase is written in a simple substitution cipher (likely shifting each letter by a fixed number, such as Caesar cipher). Let me decode it first. He explained with a story: v → e
Imagine you put your letter inside a locked box (encryption). Then, instead of mailing it directly, you send it to a special tunnel entrance — a VPN server far away. The tunnel scrambles the box again, hides your home address, and gives you a temporary mask (a different IP address). The letter emerges from the tunnel’s exit, appearing to come from the server’s city, not your home. Even if someone intercepts the box, they can’t open it without the key. Then, instead of mailing it directly, you send
“What’s that?” Mia asked.