Apple Inc.

Kerry E Lynn

Richard W Mincher

Jonathan M Zweig

Alan B Oppenheimer

Michael W Ritter

Jeffery L Mullins

A method and apparatus for assigning a unique network address to a first node within a network which is arbitrarily connected. The first node may include a shared network resource, such as a networked printer device, or a modem, in addition to a stand-alone computer system. The network may include a network which is wireless, wherein various nodes comprise radio transceiver circuitry, including radio frequency modems. A first provisional network address for use in assigning the unique network address is determined by the first node. The first node broadcasts probes containing the provisional network address until a first probe response to one of the probes is received or a first interval of time elapses. If the first probe response to one of the probes is received, then the first node determines a second provisional network address and repeats selection of the address and broadcasting, until no probe response is received in the first interval of time. Using the first provisional network address, the first node broadcasts forward probes in the network until a second probe response to one of the forward probes is received by the first node or a second period of time has transpired. If a second probe response to one of the forward probes is received by the first node, then the first node determines a third provisional network address and repeats the steps of selecting, broadcasting probes and forward probes until no the response is received in the second interval of time. The final provisional network address may be used as the unique network address for the first node.

Dynamic address assignment in an arbitrarily connected network

A system for sending and responding to information requests in a wireless communications network includes a display device, a central processing unit, memory means including random access memory and read-only memory, an input device, and a transmitter/receiver. The random access memory further comprises routines for processing, sending and receiving messages over the wireless network. The present invention also comprises a method for requesting information and a method for responding to requests for information. The preferred method for handling information requests comprises the steps of: monitoring the communications channel for availability; sending an information request over the channel; receiving the information request at each node within the network; preparing responses to the information request at each node; and sending the response to the information request over the channel if it is available. The method for responding to a request for information advantageously uses the minimum number of request to solicit the minimum number of replies to the information request.

System and method for sending and responding to information requests in

A method and apparatus for decryption using cache storage wherein imported ciphertext is decrypted to produce unencrypted plaintext data. As a communication sequence containing an initialization vector and a block of ciphertext is imported, the initialization vector is applied to a cache and to a decoder. The initialization vector is then compared with other initialization vectors stored in the cache to determine whether the specific initialization vector has previously been received and stored. If the specific initialization vector is found to be stored in the cache, then the PN sequence associated with that initialization vector is written to the decoder, and the stored PN sequence is used to decode the imported ciphertext. If a determination is made that the initialization vector has not been previously received, then the read cache signal instructs the multiplexer to connect the PN generator to the decoder, and the initialization vector is used to generate a new PN sequence. In order to improve the efficiency of future ciphertext decoding utilizing this specific initialization vector, the PN sequence associated with the initialization vector is then stored in the cache together with its corresponding initialization vector. When the next block of ciphertext is received using the same initialization vector, the PN sequence need not be regenerated by the PN generator, but rather may be read from the cache as a stored sequence.

Method and apparatus for decryption using cache storage

A distributed time synchronization system and method synchronizes nodes within a frequency hopping spread spectrum (FHSS) local area network (LAN) group to a virtual master clock value. Each node system of the present invention comprises a CPU, an input device, a display device, a printer or hard copy device, a given amount of RAM and ROM memory, a data storage device, a local clock, a transmitter/receiver, an antenna, a virtual master clock processor, and a common data bus. The method of the present invention comprises the inclusion of a node's local clock value in a message just prior to transmission over the network, storage of a node's local clock value in RAM after an incoming message has been received, and the calculation of the time delay between the sending node and the receiving node by the virtual master clock processor. The virtual master clock processor utilizes this time delay in maintaining a virtual master clock value, which it uses in adjusting the value of the node's local clock at periodic intervals. This synchronizes the receiving node to the virtual master clock value. If the magnitude of the time delay exceeds a maximum allowed value, the magnitude is clamped to the maximum allowed value, thereby maintaining synchronization within a predetermined tolerance. A node can receive a message transmitted over the FHSS LAN regardless of the message address. Synchronization is therefore maintained without requiring a node to be able to communicate with any specific node within the FHSS LAN group.

Distributed time synchronization system and method

A digital encryption structure allows the varying of the computational overhead by selectively reusing, according to the desired level of security, a pseudorandom encoding sequence at the transmitter end and by storing and reusing pseudorandom decoding sequences, associated with one or more transmitters at the receiver end. A public initialization vector is combined with a secret key to produce a deterministic sequence from a pseudorandom number generator. This pseudorandom sequence in turn, is used to convert plaintext to ciphertext. The sequence may be selectively reused by storing the sequence to a transmitter memory cache and iteratively reading the sequence from memory according to a counter which controls the level of security of the encryption system. The ciphertext is decrypted on the receiver end by invertibly combining the ciphertext with the same pseudorandom sequence used by the transmitter to originally encode the plaintext. The pseudorandom sequence is independently generated by the receiver end using the original key and initialization vector used in the transmitter end. Once generated in the receiver, the pseudorandom sequence is stored in a receiver cache for reuse with each iterative use of the stored transmitter pseudorandom sequence.

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Redwood City, CA, United States of America

Kerry E Lynn