Lucent Technologies Inc.

At&t Mobility Ii LLC

At&t Intellectual Property I, LP

James Alexander Reeds, Iii

Wen-Ping Ying

Semyon B Mizikovsky

An apparatus, system and method provides an out-of-synchronization detection by using a network layer checksum. A process operating at an upper layer verifies that a checksum embedded in a network layer header is correct before encrypting and transmitting a data packet containing the header and a payload. The data packet is received through a wireless communication channel at a receiver and decrypted. A calculated checksum is calculated on the received payload at the receiver and compared to the received checksum embedded in the header. A key stream used at the receiver for decrypting the received encrypted data packets is determined to be out of synchronization with a key stream used at the transmitter to encrypt the data packets if the calculated checksum is not equal to the network layer checksum.

Apparatus, system and method for detecting a loss of key stream system synchronization in a communication system

Apparatus, system and method for detecting a loss of key stream synchronization in a communication system

A wireless communications system (,) with increased privacy. The system (,) transmits an encrypted signal between a base station (,) and a wireless terminal (,). In the forward channel, the base station (,) includes an encryptor (,) with a long code mask generator (,) that generates a rolling long code mask. The wireless terminal (,) similarly includes a decryptor (,) with a long code mask generator (,) that creates a rolling long code mask.

Cryptographic system for wireless communications

A system for delivering a security code to a cellular telephone. The cellular telephone holds a key X. The cellular telephone requests that an Authorization Center, AC, assign a security code to the cellular telephone. The AC selects a security code, and encrypts it, such that key X is effective to de-crypt the code, yet the AC does not know key X.

Security in cellular telephones

A wireless communications system (110) with increased privacy. The system (110) transmits an encrypted signal between a base station (112) and a wireless terminal (122). In the forward channel, the base station (112) includes an encryptor (130) with a nonlinear scrambler (202) that creates an key signal that has a nonlinear dependence on a long code mask M. The wireless terminal (122) similarly includes a decryptor (164) with a nonlinear scrambler (210) that creates a key signal that has a nonlinear dependence on the long code mask M.

A method an apparatus for block or stream encrypting text uses an autokeyed rotational state vector to encrypt plain text to yield cipher text. The text is stored as a block in a buffer of an arbitrary number of bytes. Each byte of plain text in the buffer encrypted to yield a byte of cipher text by using a rotational state vector, and the rotational state vector is updated or changed as a function of one or more of: the cipher text, the plain text and a key. The encryption operation is advantageously a series of alternating non-linear and linear transformations. The method of encryption is advantageously involutory in that the encryption method and apparatus for a given key is identical to the decryption method and apparatus with the same key.

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New Providence, NJ, United States of America

James Alexander Reeds, Iii