User's Manual

Wireless Security Commands
6-119
6
cipher-suite
This command defines the cipher algorithm used to encrypt the global key for
broadcast and multicast traffic when using Wi-Fi Protected Access (WPA) security.
Syntax
multicast-cipher <aes-ccmp | tkip | wep>
• aes-ccmp - Use AES-CCMP encryption for the unicast and multicast
cipher.
• tkip - Use TKIP encryption for the multicast cipher. TKIP or AES-CCMP can
be used for the unicast cipher depending on the capability of the client.
• wep - Use WEP encryption for the multicast cipher. TKIP or AES-CCMP
can be used for the unicast cipher depending on the capability of the client.
Default Setting
wep
Command Mode
Interface Configuration (Wireless-VAP)
Command Usage
• WPA enables the access point to support different unicast encryption keys
for each client. However, the global encryption key for multicast and
broadcast traffic must be the same for all clients.
• If any clients supported by the access point are not WPA enabled, the
multicast-cipher algorithm must be set to WEP.
• WEP is the first generation security protocol used to encrypt data crossing
the wireless medium using a fairly short key. Communicating devices must
use the same WEP key to encrypt and decrypt radio signals. WEP has
many security flaws, and is not recommended for transmitting highly
sensitive data.
• TKIP provides data encryption enhancements including per-packet key
hashing (i.e., changing the encryption key on each packet), a message
integrity check, an extended initialization vector with sequencing rules, and
a re-keying mechanism. Select TKIP if there are clients in the network that
are not WPA2 compliant.
• TKIP defends against attacks on WEP in which the unencrypted
initialization vector in encrypted packets is used to calculate the WEP key.
TKIP changes the encryption key on each packet, and rotates not just the
unicast keys, but the broadcast keys as well. TKIP is a replacement for
WEP that removes the predictability that intruders relied on to determine the
WEP key.