摘要:
A system for communicating a sequence of information symbols using a chaotic sequence spread spectrum signal. The system includes a transmitter (402) for transmitting a signal including the information symbols, the information symbols encoded into the signal using a first chaotic sequence of chips generated at the transmitter. The system also includes a receiver (404) configure to receive the signal and extract the information symbols from the signal, the information symbols extracted using a second chaotic sequence of chips generated at the receiver. In the system, the first and the second chaotic sequences are identical and synchronized in time and frequency, each of the sequence of symbols is associated with a randomly generated threshold symbol energy value, and the portion of chips in the first and the second chaotic sequences associated with each of the plurality of information symbols is selected based on the associated threshold symbol energy value.
摘要:
A cryptographic system (CS) is provided. The CS (800) comprises a data stream receiving means (DSRM), a generator (702), a mixed radix converter (MRC) and an encryptor (908). The DSRM (902) is configured to receive a data stream (DS). The generator is configured to selectively generate a random number sequence (RNS) utilizing a punctured ring structure. The MRC (704) is coupled to the generator and configured to perform a mixed radix conversion to convert the RNS from a first number base to a second number base. The encryptor is coupled to the DSRM and MRC. The encryptor is configured to generate an altered data stream by combining the RNS in the second number base with the DS. The punctured ring structure and the MRC are configured in combination to produce an RNS in the second number base which contains a priori defined statistical artifacts after the mixed radix conversion.
摘要:
A method is provided for tamper detection of a transmitted signal. The method is comprised of generating a first digital data signal having a first data rate. The method is also comprised of generating a second digital data signal having a second data rate. The method is further comprised of concurrently transmitting the first digital data signal at a first carrier frequency using a first modulation format and the second digital data signal at a second carrier frequency using a second modulation format. The method includes selecting the second carrier frequency and a bandwidth of the second digital data signal so that the second digital data signal is contained within a frequency spectrum defined by a bandwidth of the first digital data signal. The method also includes verifying an integrity of the first digital data signal at a remote receiver based on defection at the remote receiver of the second digital data signal. A system (100) is also provided for generating a tamper-protected transmitted signal.
摘要:
A cryptographic system (CS) comprised of generators (502), (504), (510), an encryption device (ED), and a decryption device (DD). The generator (502) generates a data sequence (DS) including payload data. The generator (504) generates an encryption sequence (ES) including random numbers. The ED (506) is configured to perform a CGFC arithmetic process. As such, the ED is comprised of a mapping device (MD) and an encryptor. The MD is configured to map the DS and ES from Galois field GF[pk] to Galois extension field GF[pk+1]. The encryptor is configured to generate an encrypted data sequence (EDS) by combining the DS and ES utilizing a Galois field multiplication operation in Galois extension field GF[pk+1]. The generator (510) is configured to generate a decryption sequence (DS). The DD (508) is configured to generate a decrypted data sequence by performing an inverse of the CGFC arithmetic process utilizing the EDS and DS.
摘要:
A method is presided for masking a process used in generating a random number sequence. The method includes generating a random number sequence. This step involves selectively generating the random number sequence utilizing a ring structure which has been punctured. The method also includes performing a mixed radix conversion to convert the random number sequence from a first number base to a second number base. The method further includes puncturing the ring structure by removing at least one element therefrom to eliminate a statistical artifact in the random number sequence expressed in the second number base. The first number base and second number base are selected so that they are respectively defined by a first Galois field characteristic and a second Galois field characteristic.
摘要:
Systems (100) and methods for selectively controlling access to data streams communicated from a first communication device (FCD) using a timeslotted shared frequency spectrum and shared spreading codes. Protected data signals (1301, . . . , 130S) are modulated to form first modulated signals (1321, . . . , 132S). The first modulated signals are combined with first chaotic spreading codes to form digital chaotic signals. The digital chaotic signals are additively combined to form a protected data communication signal (PDCS). The PDCS (136) and a global data communication signal (GDCS) are time division multiplexed to form an output communication signal (OCS). The OCS (140) is transmitted from FCD (102) to a second communication device (SCD) over a communications channel. The SCD (106, 108, 110) is configured to recover (a) only global data from the OCS, or (b) global data and at least some protected data from the OCS.
摘要:
A receiver (104) in communications system (100) includes an antenna system (302) for receiving a composite signal comprising multi-path components associated with the multi-path images of a transmitted signal. The receiver also includes a correlation system (368) for correlating the received composite signal with a spreading sequence using different time-offset values to generate time-offset de-spread signals associated with at least a portion the multi-path images, where the spreading sequence is based on sequence of discrete-time chaotic samples. The receiver further includes receiver fingers (108a-108n) for generating synchronized de-spread signals from the time-offset de-spread signals based at least on said time-offset values. The receiver also includes a combiner (350) for combining the de-spread signals into a combined coherent de-spread signal.
摘要:
Systems and methods for code-division multiplex communications. The methods involve forming orthogonal or statistically orthogonal chaotic spreading sequences (CSC1,1, CSCD,1), each comprising a different chaotic sequence. The methods also involve generating an offset chaotic spreading sequence (CSC1,2, CSC1,3, . . . , CSC1,K(1), CSCD,2, . . . , CSCD,K(D)) which is the same as a first one of the orthogonal or statistically orthogonal chaotic spreading sequences, but temporally offset. Spread spectrum communications signals (SSCs) are each respectively generated using one of the orthogonal or statistically orthogonal chaotic spreading sequences. Another SSC is generated using the offset chaotic spreading sequence. The SSCs are concurrently transmitted over a common RF frequency band.
摘要:
A cryptographic system (CS) comprised of generators (502), (504), (510), an encryption device (ED), and a decryption device (DD). The generator (502) generates a data sequence (DS) including payload data. The generator (504) generates an encryption sequence (ES) including random numbers. The ED (506) is configured to perform a CGFC arithmetic process. As such, the ED is comprised of a mapping device (MD) and an encryptor. The MD is configured to map the DS and ES from Galois field GF[pk] to Galois extension field GF[pk+1]. The encryptor is configured to generate an encrypted data sequence (EDS) by combining the DS and ES utilizing a Galois field multiplication operation in Galois extension field GF[pk+1]. The generator (510) is configured to generate a decryption sequence (DS). The DD (508) is configured to generate a decrypted data sequence by performing an inverse of the CGFC arithmetic process utilizing the EDS and DS.
摘要:
A cryptographic system (CS) is provided. The CS (500) is comprised of a data stream receiving device (DSRD), a chaotic sequence generator (CSG) and an encryptor. The DSRD (602) is configured to receive an input data stream. The CSG (300) includes a computing means (3020, . . . , 302N-1) and a mapping means (304). The computing means is configured to use RNS arithmetic operations to respectively determine solutions for polynomial equations. The solutions are iteratively computed and expressed as RNS residue values. The mapping means is configured to determine a series of digits in the weighted number system based on the RNS residue values. The encryptor is coupled to the DSRD and CSG. The encryptor is configured to generate a modified data stream by incorporating or combining the series of digits with the input data stream.