Final answer:
WEP fails to provide data integrity because it uses CRC-32 for integrity checking, which is susceptible to intentional forgery, and because it employs a static encryption key that, once discovered, allows attackers to create seemingly valid messages.
Step-by-step explanation:
How WEP Fails to Provide Data Integrity
WEP (Wired Equivalent Privacy) is a security protocol that was designed to provide a wireless local area network (WLAN) with a level of security and privacy comparable to what is usually expected of a wired LAN. However, WEP has several well-known vulnerabilities that affect its ability to provide data integrity. Data integrity refers to the assurance that data has not been altered in an unauthorized manner during transmission.
One of the key reasons WEP fails to provide strong data integrity is its use of the CRC-32 (Cyclic Redundancy Check) for integrity checking. CRC-32 is effective for accidental errors, but it is not secure against intentional tampering or forgery. Attackers can easily alter a WEP-protected packet and recalculate the CRC value so that the packet appears to be valid.
Additionally, because WEP uses a static encryption key that is shared among all users of the network, if an attacker discovers the key, they can not only decrypt messages but also create new messages with valid checksums, further compromising data integrity. Advanced encryption methods, such as those used by WPA (Wi-Fi Protected Access) and WPA2, include stronger integrity checks that are specifically designed to prevent such attacks, highlighting the weakness of WEP in comparison.