Three features of the AirPort Card help to maintain the security of data transmissions:
The system uses direct-sequence spread-spectrum (DSSS) technology that uses a multi-bit spreading code that effectively scrambles the data for any receiver that lacks the corresponding code.
The system can use a table of authentic network client ID values to verify each client's identity before granting access to the network.
When communicating with a base station, the system encrypts the data using Wired Equivalent Privacy (WEP) with a 40-bit security key.