User's Manual

APPENDIX D
SECURITY
Revised: 5 Dec 12 APX D-2 EST P/N AA107-210CM
128-BIT WEP
The 128 WEP uses a particular algorithm called RC4 encryption to encode and decode tr
affic that is based on a 104-bit encryption
key and a 24-bit Initialization Vector (IV). RC4 starts with a relatively short encryption key (104 bits) that is expanded into a
nearly infinite stream of keys to accompany the stream of packets.
The basic concept of RC4 is good, but the way it’s implemented in WE
P leaves it open to compromise. The researchers that test
the integrity of the system usually focus on one piece of the implementation, the Initialization Vector (IV).
The IV (24 bits) is the algorithm component that’s supposed to keep expanded keys from repeating. From t
he researcher’s point
of view, a high-volume access point is mathematically guaranteed to reuse the same key stream at least once a day. When this
happens, it’s called an IV collision this becomes a soft spot to enter the system.
The researchers aren’t saying that it’s easy to break into the system, or that it’s being done on a regular basis, only that it is
possible and admi
nistrators should consider ways to reduce the possibility
ACCESS CONTROL LIST (ACL)
The ACL is one of the simplest yet most secure methods of network security. The ACL is a configurable MAC filter in the Model
192E th
at can be set to allow specific MAC address on the wireless network by individual address or address ranges. The same
filter can also be set to reject individual MAC addresses or address ranges.
The MAC address is a unique, 6 hexadecimal field addresses assigned at t
he manufacturer that can not be changed. The MAC
address is traceable through the IEEE governing body to the manufacturer and is the “fingerprint” for all Ethernet devices.
Using a combination of either the WPA or 128-Bit WE
P encryption and the ACL filter provide the ESTeem an extremely secure
wireless networking layer.