Encryption is the method used to protect the confidentiality of data flowing between a transmitter and a receiver. Encryption in WiMAX Technology involves taking a stream or block of data to be protected, called plain text, and using another stream or block of data, called the encryption key, to perform a reversible mathematical operation to generate a cipher text. The cipher text is unintelligible and hence can be sent across the network without fear of being eavesdropped.
The receiver does an operation called decryption to extract the plaintext from the cipher text, using the same or different key. When the same key is used for WiMAX encryption and decryption, the process is called symmetric key encryption. This key is typically derived from a shared secret between the transmitter and the receiver and for strong encryption typically should be at least 64 bytes long. When different keys are used for encryption and decryption, the process is called asymmetric key encryption. Both symmetric and asymmetric key encryptions are typically used in broadband wireless communication systems, each serving different needs.