Confidentiality is the principle that is at risk when a digitally-signed e-mail is delivered over a wireless network protected with Wired Equivalent Privacy (WEP) protocol. Confidentiality is the principle that ensures that the data or information is only accessible or disclosed to authorized parties, and that it is protected from unauthorized access or disclosure. WEP is an outdated and insecure protocol that encrypts the wireless network traffic using a shared key that can be easily cracked or compromised by attackers. If an attacker intercepts the wireless network traffic, they can decrypt the WEP-encrypted packets and read the contents of the e-mail, which may contain sensitive or confidential information.