Question

if eve parks a van outside alices house, she can use sensitive tempest equipment to identify each individual keystroke that alice makes on her computer. this would allow eve to intercept the message as it is typed into the computer, before it is encrypted. to defend against tempest attacks, companies are already supplying shielding material that can be used to line the walls of a room to prevent the escape of electromagnetic signals. in this excerpt, the author explains why computers are easily stolen. why keyboards are unsanitary. how computer security can be broken. how friends share secret messages.

Explanation:

The text describes how Eve can use tempest equipment to intercept messages before encryption by detecting keystrokes, and also mentions a defense - shielding material. It focuses on the vulnerability of computer security and how it can be breached.

Answer:

how computer security can be broken.