What does TKIP do?

• A. A 128 bit per packet key is used meaning that it dynamically generates a new key for each packet
• B. Uses a single session key for all packets
• C. Generates a 256-bit static key
• D. Provides message authentication for IP headers only

Answer: (A)

TKIP strengthens wireless security by creating a fresh key for every frame. It starts with a 128-bit Temporal Key shared by both ends, and for each packet it derives a new 128-bit per-packet key from that Temporal Key together with a per-frame IV (sequence counter) and the sender’s MAC address. That per-packet key is then used to encrypt the payload with RC4. Because the key changes with every packet, key reuse attacks that plagued WEP are mitigated. So, describing TKIP as using a 128-bit per-packet key that’s generated for each packet is the correct understanding. It isn’t just one session key for all packets, it isn’t a static 256-bit key, and its primary purpose isn’t limited to IP header authentication.