Abstract: Method and apparatus for controlling access to a secure network, system or application is disclosed. In one embodiment, an apparatus for requesting authentication includes a storage medium that stores a cryptographic key, a processor that generates an access code using the cryptographic key, a converter that converts the access code into sound waves, and an audio output unit that outputs the sound waves encoded with the access code for authentication. An apparatus for granting authentication includes a storage medium that stores a cryptographic key, an audio input unit that receives sound waves encoded with a access code, a converter that recovers the access code from the sound waves, and a processor that generates a second access code using the cryptographic key and grants authentication if the access code corresponds to the second access code.

Abstract: Method and apparatus for secure transmissions. Each user is provided a registration key. A long-time updated broadcast key is encrypted using the registration key and provided periodically to a user. A short-time updated key is encrypted using the broadcast key and provided periodically to a user. Broadcasts are then encrypted using the short-time key, wherein the user decrypts the broadcast message using the short-time key. One embodiment provides link layer content encryption. Another embodiment provides end-to-end encryption.

Abstract: Apparatus and method for generating a key stream is disclosed. In one embodiment, a cryptographic function is applied on input values selected from a first array of values to generate output values. Mask values are then selected from a second array of values and combined with the output values to generate a key stream block for the key stream. The first and second arrays are finite and may be implemented by a linear feedback shift register.