Final answer:
The encryption standard that offers the least security on older wireless devices is WEP (Wired Equivalent Privacy). Compared to the more modern WPA and WPA2 standards, WEP has significant security flaws.
Step-by-step explanation:
The encryption standard found on older wireless devices that provide minimal security is WEP (Wired Equivalent Privacy). WEP was introduced in 1999 and was the original Wi-Fi security protocol. However, it has been found to have several security flaws making it the least secure option compared to more modern standards like WPA (Wi-Fi Protected Access) and WPA2. The AES (Advanced Encryption Standard) is a more secure encryption method that can be used in conjunction with WPA2, making it a preferable choice for protecting a wireless network.