Symbol Technologies AP-4131 manual Data Encryption

Introduction

A TIM is a compressed virtual bitmap identifying the AP associated MUs in PSP mode that have buffered directed messages. MUs issue a poll request when APs issue a TIM. A beacon with the broadcast-indicator bit set causes the MU to note DTIM Count field value. The value informs the MU of the beacons remaining before next DTIM. This ensures the MU turns on the receiver for the DTIM and the following BC/MC packet transmissions.

1.3.9Data Encryption

Any wireless LAN device (including Spectrum24 devices operating on a wireless network) faces possible information theft. Theft occurs when an unauthorized user eavesdrops to obtain information illegally. The absence of a physical connection makes wireless links particularly vulnerable to this form of theft.

Encryption becomes the most efficient method in preventing information theft and improving data security. Encryption entails scrambling and coding information, typically with mathematical formulas called algorithms, before the information is transmitted. An algorithm is a set of instructions or formula for scrambling the data. A key is the specific code used by the algorithm to encrypt or decrypt the data. Decryption is the decoding and unscrambling of received encrypted data.

The same device, host computer or front-end processor, usually performs both encryption and decryption. The data transmit or receive direction determines whether the encryption or decryption function is performed. The device takes plain text, encrypts or scrambles the text typically by mathematically combining the key with the plain text as instructed by the algorithm, then transmits the data over the network. At the receiving end another device takes the encrypted text and decrypts, or unscrambles, the text revealing the original message. An unauthorized user can know the algorithm, but cannot interpret the encrypted data without the appropriate key. Only the sender and receiver of the transmitted data know the key.

Symbol uses the Wired Equivalent Privacy (WEP) algorithm, specified in IEEE 802.11 section 8, for encryption and decryption. WEP uses the same key for both encrypting and decrypting text. Typically an external key service distributes the key. Users should change the key often for added security.

AP-4131 Access Point Product Reference Guide 25