Abstract: An apparatus and method of detecting a transmission code from a received signal, where the transmission code is composed of a plurality of dithered codes. The codes can be dithered either by varying the length of the code or varying the phase of the code according to a dither pattern and can be a stationary dither pattern that is fixed and generally known. The method includes detecting the plurality of dithered codes, and detecting the long code based on the detected dithered codes. A detection signal is generated for each detected dither code, the detection signals are combined, and the long code is detected based on the combination of detection signals. If the composite code includes M dithered codes, the correlation signals are combined by summing the M correlation sums to generate a present final sum.

Abstract: A received PDU is sequentially identified by an n-bit frame number (FN) and an m-bit hyper frame number (HFN), which are synchronously maintained on first and second stations. The second station determines an activation time at which a ciphering key change is to occur, and composes a security mode command that includes an identifying FN corresponding to the activation time, and x least-significant bits (LSBs) from the HFN of the identifying FN. The second station transmits the security mode command to the first station. The x LSBs contained in the security mode command enable the first station to resolve cyclical ambiguities of the identifying FN to properly construct an application time. The first station uses a first ciphering key to decrypt PDUs with FNs sequentially prior to the application time, and uses a second ciphering key to decrypt PDUs with FNs sequentially on or after the application time.

Abstract: A method and apparatus for re-synchronizing a stream cipher during soft handoff. Transmitted quasi-secret keying information is used with a secret key to reinitialize a stream cipher generator located in a base station and a stream cipher generator located in a travelling mobile station. Since the quasi-secret keying information is uniquely determined according to each base station in the wireless telephone system, a base station's quasi-secret keying information and a shared secret key can also be used to create a new key. Thus, as the mobile station travels from one base station to another base station, a unique new key is generated for each base station.

Abstract: A method and apparatus are provided for encrypting a stream of data transmitted within a frame. The method includes determining a first initialization state in a first preselected interval, and determining the first initialization state in a second preselected interval, wherein the second preselected interval is less than the first preselected interval. The method includes generating a key stream in response to determining the first initialization state in the second preselected interval, and encrypting at least one bit of the stream of data with at least one bit of the key stream.

Abstract: A chaotic receiver estimation engine and method of use. The estimation engine synchronizes and recovers data and performs its decision and tracking processes by mapping probability calculation results onto chaotic dynamics via a strange attractor geometrical approximation. Restrictive standard chaotic synchronization requirements of either a stable/unstable subspace separation or a chaotic system inversion are not required. The receiver determines and models both the logical zero and logical one versions of the strange attractor and the transmitted chaotic sequence probability density function (PDF). Two estimates of the transmitted value are created from each received iterate by probability and the transmitted PDF calculations. A third estimate is generated from the chaotic processing of the previous receiver final decisions. The three estimates are combined using a probability-based weighted average to form the initial current decision.

Abstract: An apparatus and method for transmitting and receiving cryptographic information which provide a mechanism for resynchronization between a transmitter and receiver of the cryptographic information. A cryptographic synchronization counter at the transmitter generates a transmitter signature tag. A corresponding cryptographic synchronization counter at the receiver generates a receiver signature tag. Information is ciphered and the transmitter signature tag is appended to the ciphered information. The ciphered information is received. The transmitter signature tag is compared to the receiver signature tag and the cipher text is decipher into plain text if the tags are equal. If the tags are not equal, the receiver crypto-sync counter is incremented and a new receiver signature tag is calculated to determine if the receiver is resynchronized (i.e., tags are equal) to the transmitter. If after a certain number of increments, resynchronization does not occur, a resynchronization procedure is initiated.

Abstract: A method of transmission level security, and a corresponding transmission security system, the method consists of the steps of: forming a plurality of digital signals representing a symbol to be transmitted over a communication medium, wherein respective ones of the plurality of digital signals are modulated onto respective ones of a plurality of subcarriers according to a multiple carrier modulation scheme; and introducing a predetermined group delay distortion in one or more of the plurality of subcarriers, such that portions of the one or more of the plurality of subcarriers will be received outside of a time window corresponding to the symbol at a receiver. In one implementation, an equipped receiver substantially removes the predetermined group delay distortion such that the portions of the one or more of the plurality of subcarrier fit within the time window.

Abstract: A ciphered message contained in a radio signal is displayed as it is if a code number contained in a received radio signal does not coincide with a preliminarily registered code number. On the other hand, if the code number contained in the radio signal coincide with the preliminarily registered code number, the message is deciphered and displayed on a display portion when a code number input from an input portion coincides with a received code number.

Abstract: Codeword synchronization and scrambler synchronization in a block-coded serial communications link are accomplished by (i) substituting a specific comma control codeword for a selected codeword value occurring in the output of a scrambler receiving an input data stream, and (ii) using selected polarity-independent bits of the block-coded scrambled bit stream to convey samples of the scrambler state. Inversion of received control codewords indicates polarity inversion somewhere along the link, enabling automatic polarity correction to be applied.

Abstract: A trainable transmitter comprises a transmitter, code-generation circuitry and a removable, plug-in data module. The data module includes information necessary for generating a code for a specific security system, such as a garage door opener. Preferably, the data includes a cryptographic algorithm and the frequency at which the wireless signal is to be generated. The code-generation circuitry accesses the data in the data module to generate a code, which is then transmitted by the transmitter. A variety of data modules are provided. A user installs a data module which corresponds to the security system to be accessed.

Abstract: A communication system is provided herein for transmitting frames across a channel. The frames may be transmitted in single-input, single-output (SISO) and/or multi-input, multi-output (MIMO) communication systems. One such frame includes at least one training symbol, each having a cyclic prefix and a training block. The time length NI of the training block is equal to an integer fraction I of the time length of a data block, i.e., NI=N/I. Furthermore, the time length G of the cyclic prefix is an integer fraction of the time length NI. For example, G may be equal to NI/4 or 25% of NI. The training symbols provide coarse and fine time synchronization, coarse and fine frequency synchronization, channel estimation, and noise variance estimation.

Abstract: An encryption and decryption method applied upon transmitting a plaintext in a communication network containing plural subscriber ends is provided.

Abstract: A system and method for data communication with adaptive security in which a send host transmits a data stream to a receive host in packets which contain an authentication data block with an authentication header and a signature block. The authentication header advantageously contains various fields including a verification type, a security algorithm, a minimum security level, a target security level, and an actual security level. The receive host adaptively performs verification of the data packets using varying security levels based in part on the availability of security operations per second (SOPS) in the receive host. Where a data stream in the receive host is delayed by a security processing bottleneck, the receive host may alter the verification type, security algorithm, or the actual security level to speed up the processing of the data stream by reducing the amount of security processing performed.

Abstract: A method for a user equipment (UE) to establish a communication link comprising the steps of receiving an input communication signal at an initial search frequency, processing the input communication signal to retrieve a primary scrambling code, the retrieval of the primary scrambling code being a code decision, and adjusting the search frequency of the UE in response to the code decision.

Abstract: The present invention is a user equipment (UE) comprising a system for establishing a communication link. The system includes a first, second and third module and a controller. The first module first processes a communication signal and generates an index value associated with a primary synchronization code within the communication signal. The second module second processes the communication signal in response to the index value and a peak sample extracted from the first module and retrieves a code group number, slot offset and secondary synchronization code. The third module third processes the communication signal and retrieves a primary scrambling code in response to the code group number and the slot offset. The controller, which is coupled to the first, second and third modules, controls the adjustment of a search frequency of the UE to retrieve the primary scrambling code in the communication signal.

Abstract: A transmission apparatus performs a one-way operation on the plaintext to generate a first value and transmits the first value, generates first additional information, performs an invertible operation on the plaintext and the first additional information to generate connected information, encrypts the connected information according to an encryption algorithm to generate ciphertext, and transmits the ciphertext.

Abstract: A method of transmission level security, and a corresponding transmission security system, the method consists of the steps of: forming a plurality of digital signals representing a symbol to be transmitted over a communication medium, wherein respective ones of the plurality of digital signals are modulated onto respective ones of a plurality of subcarriers according to a multiple carrier modulation scheme; and introducing a group delay distortion in one or more of the plurality of subcarriers, wherein a peak-to-peak variation of the group delay distortion is greater than a guard time interval corresponding to the symbol, such that portions of the one or more of the plurality of subcarriers will be received outside of a time window corresponding to the symbol at a receiver.

Abstract: Security key synchronization is maintained between nodes in an optical communications system utilizing out-of-band signaling to indicate that a new key is being used to encrypt subsequent information blocks at the transmitting point and that the new key should be used to decrypt subsequent information blocks at the receiving point. A switch-to-new-key code can be selected from a group of unused codes in an eight bit to ten bit encoding scheme. The switch-to-new-key code can replace an idle code that is used to create sufficient spacing between information blocks. Receipt of the switch-to-new-key code indicates that the new key is being used to encrypt subsequent information blocks at the transmitting point and triggers a switch to the new key for decrypting subsequent information blocks at the receiving point.

Abstract: Disclosed is a method and apparatus for updating an on-board clock device, for instance a clock that is embodied on a time-stamping cipher module, to compensate for individual deviation from an external time-source. Typically, a computer system, such as a network server, is in communication with a cryptographic system comprising a plurality of time-stamping cipher modules that provide dedicated time-stamping and cryptographic functions for the computer system. Due to individual clock drift, the synchronization of time values provided by the on-board clocks of the plurality of modules tends to decrease over time. Periodically, each module provides a signal indicating a time associated with the module to each of other modules of the plurality of modules for determining a synchronization between the modules and for detecting modules that are other than synchronized with the synchronized modules.

Abstract: A self-inverting enhanced CMEA encryption system suitable for use in wireless telephony. An unprocessed text message is introduced into the system and subjected to a first iteration of a CMEA process, using a first CMEA key to produce a first intermediate message, a first intermediate processed text message, a first intermediate ciphertext message or the like. The first intermediate processed text message is subjected to a further iteration of the CMEA process, using a second CMEA key, to produce a second intermediate processed text message. The second intermediate processed text message is subjected to a final iteration of the CMEA process, using the first CMEA key, to produce the final processed text message. Security may be additionally enhanced by subjecting each message to an input/output transformation before and after each iteration of the CMEA process.

Abstract: The present invention comprises the bus reset detection circuit 6 detecting a bus reset signal from the network initiation/control state machine, the bus reset identification code generation circuit 8 and the bus reset identification code detection circuit 11 detecting a bus reset identification code and the bus reset signal generation circuit 16 which outputs a bus reset signal to the network initiation/control state machine.

Abstract: Disclosed is an encrypting speech processor architecture that provides enhanced security without the use of external cryptosync and with minimal speech degradation. This is accomplished by incorporating a block encryptor and a keystream generator (instead of a fixed secret mask encryption scheme, such as those implemented in voice ciphers) for encrypting blocks of encoded speech bits at a transmitter side. The block encryptor employs an invertible cryptographic algorithm and internal cryptosync to convert a first block of encoded speech bits into a first ciphertext block. The first ciphertext block is used to generate a keystream, which is then used to encrypt a second ciphertext block.

Abstract: A system, method, and data structure provide for securely synchronizing passwords and/or other information between systems. The password-related information is stored in the systems in a secure manner, and a user or some other, external agent participates actively in the transmission of a new password between systems. A password update file is communicated or shared between systems to synchronize passwords.

Abstract: An apparatus and method for detecting erroneous initialization vectors transmitted over a communications channel and maintaining cryptographic synchronization by comparing a received vector with a predicted correct vector. The vectors are random-like in nature by utilizing a pseudo-random number generator having a long overall cycle length. If the level of bit errors of the comparison is relatively small, considering the predicted vector is considered correct and used for synchronization, but if the number of bit errors of the comparison is relatively large, the predicated vector is considered in correct.

Abstract: A novel method and apparatus for scrambling a television signal includes using a synchronization separator to separate a synchronization signal from an input audio-visual signal. The synchronization signal is then used to regulate an oscillator producing an audio carrier signal. In this manner, the audio-visual signal is transmitted without the component synchronization signal rendering it useless to a conventional television receiver. The descrambler and descrambling method of the invention involve removing the audio carrier signal from the scrambled signal and using the audio carrier signal to generate the color sub-carrier signal and a vertical time frame reference signal necessary to synchronize the transmitted audio visual signal for display.

Abstract: Threshold cryptography (secret sharing) is used for exchanging a secret between a server and a client over an unreliable network. Specifically, a secret is computationally divided into N shares using a threshold encryption scheme such that any M of the shares (M less than or equal to N) can be used to reconstruct the secret. The N shares are spread over a number of transmitted messages, with the assumption that some number of the messages including a total of at least M shares will be received by the client. Upon receiving at least M shares, the client uses the at least M shares to reconstruct the secret using the threshold encryption scheme.

Abstract: Encoder and decoder microchips suitable for use in secure unidirectional remote control devices. The encoder microchip includes circuits for performing and encoding function on an identification number embedded in the microchip and a combination of a characterization number and a stepping counter value, so as to generate a transmission value which is only decidable by a related decoding function having access to the same identification number. The decoder microchip includes circuits for decoding the transmission value into a decoded characterization number and a decoded counter value and circuits for comparing the decoded counter value with a decoded counter value range. The encoder and decoder microchips are also provided with means for synchronizing the decoder microchip with a particular encoder microchip which has generated a synchronization command.

Abstract: An agent is permanently resident in a server as software for the purpose of cryptographic processing. In addition, another agent that is described in mobile code and contains a program for the purpose of cryptographic processing is also stored in the server. When data that are to be sent and received between the server and a client are encrypted, the agent that is described in mobile code is sent from the server to the client. When the client receives data that were encrypted in the server, it reproduces those data by decryption using the received agent.

Abstract: A state synchronized cipher text scrambler is disclosed. The state synchronized cipher text scrambler enables multiple data streams to be scrambled in parallel in such a way that the data streams are uncorrelated with respect to each other and there is a large fixed delay relationship between the scrambler bits over the multiple streams. This enables a receiver to correctly identify the ordering of the multiple data streams with respect to each other automatically, correct for any polarity or wire-swap misconnections and align the received multiple data streams despite differential delays between the data streams.

Abstract: The capabilities of a cryptographic module are controlled by a crypto configuration control (CCC) register that is initialized by one or more self-signed commands that are preformulated and signed with the digital signature key of the crypto module itself. The crypto module accepts a self-signed command only if the self-signature can be validated using the signature verification key of the module. In one implementation, the final configuration is determined by a single self-signed command. In another implementation, a first self-signed command is used to create an temporary configuration that allows one or more initialization authorities to issue additional commands fixing the final configuration. The self-signed commands are maintained separately from the crypto module and are distributed to the end user either physically or electronically.

Abstract: An encryption key generation system generates encryption keys at both an originating terminal and a terminating terminal of a wireless network. A central controller generates a shared secret based on the identification information of a requesting terminal and a first number, which may be random. The central controller broadcasts the first number to all terminals. A second number is generated by the central controller incorporating the shared secret data and the terminating terminal's identification information. The requesting terminal generates the shared secret data using the first number and predetermined algorithms and generates an encryption key based on the first number and the shared secret data. The terminating terminal decodes the shared secret data from the second number, and generates the same encryption key using the first number and the shared secret data.

Abstract: An apparatus and method for concealing data bursts in an analog scrambler using audio repetition. What otherwise would be periodic data bursts appearing at the audio output are replaced with samples from audio portions of the multiplexed signal. Preferably the replaced audio samples come from immediately past portions of the audio of the signal. The data bursts are therefore effectively concealed from the audio output which improves on the degradation of audio otherwise caused by the data bursts that are mixed in periodically with the audio portions of the signal.

Abstract: An audio signal processing method and unit for scrambling and descrambling audio signals accompanying video signals. The audio signal processing method comprises steps of dividing digital audio signals into data blocks synchronized to video signals, and then switching the order of adjacent odd and even blocks. The audio signal processing unit comprises a synchronizing signal detector for detecting the synchronizing signal in the video signal; a timing controller for generating a sampling clock signal for A/D conversion, sampling signal for D/A conversion, and system clock from the synchronizing signal; an A/D converter for converting the analog audio signal to digital audio signal using the sampling clock for A/D conversion; a scrambler for dividing the digital audio signal into data blocks using the system clock and switching adjacent odd and even blocks; and a D/A converter for converting the output signal of the scrambler to the analog audio signal using the sampling clock for D/A conversion.

Abstract: A method and an apparatus are provided for securely identifying a mobile user while avoiding trackability of his/her movements, i.e. it provides a way for a secure user identification in secrecy. The gist is to encrypt the user's identifier, and/or his/her password, and a synchronization indication, preferably a fixed time interval, under a secret one-way function and sending the encrypted message, called a "dynamic user identifier", to the user's "home authority" where he/she is registered. The home authority comprises correspondence tables listing, pre-computed for every time interval (or another chosen synchronization), the dynamic user identifiers and the corresponding true identity of the user and can thus quickly decide whether the received encrypted message originates from a registered user. On the other hand, an intruder is neither able to detect from the encrypted messages the identity of the user nor can he/she track a user's moves.

Abstract: A remote-control unit for vehicles in which an immobilizer facility and keyless entry facility are united to enable bidirectional transmission. Further, a cost reduction is achieved by decreasing the number of parts, and labor required for maintenance is diminished. A remote-control unit for vehicles includes a circuit 16 for receiving a cryptographic code CR from a vehicle when a key 10 is fitted into a key cylinder 21, a circuit 17 for storing a cryptographic code, a control circuit for producing a first cipher system code CS1 in response to a cryptographic code, and producing a second cipher system code CS2 in response to actuation of a manual switch 12, and a transmission circuit 15 for transmitting the cipher system codes in the form of radio waves to the vehicle.