183 results about "Keystream" patented technology

The invention belongs to the technical field of information security, and particularly relates to a color image encryption method based on cellular neural network hyperchaos and a DNA sequence. The method provided by the invention comprises the steps of separating red, green and blue three primary color components of a color plaintext image; updating and generating parameters and initial values of a six-order cellular neural network hyperchaotic system and a Logistic-Sine mapping system through the plaintext image, respectively carrying out iterative operation on the two chaotic systems, and obtaining red, green and blue components of an encrypted image according to a DNA encoding rule and a DNA decoding rule; and finally, changing the pixel values of the encrypted image through key stream and a bitwise XOR operation to obtain a final ciphertext image. The decryption is a reverse operation of the encryption process. Compared with the existing image encryption method, the color image encryption method provided by the invention has the advantages of high security, good encryption effect, strong robustness, no information loss and the like, and thus being capable of being widely used in military, remote sensing, remote medical treatment, commerce and other fields.

The invention discloses a method for generating a variable parameter chaotic signal, and a chaotic secure communication system. The method comprises the following steps: firstly, chaotic mapping is used to generate the chaotic signal; then a parameter set of the chaotic mapping is determined in advance, so as to process any pseudorandom signal, and enable the state of the pseudorandom signal and the elements of the parameter set to be in one-to-one correspondence; and a corresponding parameter is chosen to generate the variable parameter chaotic signal by chaotic mapping according to the state of the pseudorandom signal. The system comprises a chaotic signal generating module, an analog-to-digital conversion module, a parameter transformation module, a coding module, a multi-path choice switch, an encryption/decryption module, an encrypted message data cache, a plaintext data cache and a control module. The invention can increase the complexity of the output of the chaotic signal or a chaotic sequence, and effectively resist the analysis of the nonlinear prediction technology based on phase-space reconstruction. The output digital chaotic sequence can be taken as a pseudorandom number sequence or key stream to encrypt data; the output continuous chaotic signals can be used for designing a secret communication system based on chaos synchronization .

An approach for securely transmitting and storing data is described. A sending host generates a random sequence of characters as a keystream as a one-time pad. The keystream is bitwise combined with plaintext using an exclusive-OR operation to create ciphertext. The keystream and ciphertext are routed over physically separate communication paths to a receiving host, which decrypts by applying the keystream to the ciphertext using exclusive-OR, The separately routed paths may be established using MPLS labeling or strict route options.

The present invention relates to a cryptosystem. A keystream table [Ks] is a virtual data space. Every data of 1 byte in a secondary ciphertext E₂ provides a vector directional component IR. The data Ks (IR) in the keystream table [Ks] designated by the directional component IR of the vector is recognized as the quantitative component of the vector. By handling a secondary ciphertext E₂ of 1 byte as the address in the keystream table [Ks], the secondary ciphertext E₂ can be recognized as the directional component of the vector. A logical operation for the data Ks (IR) is performed, and the internal vector data V is sequentially replaced every 1 byte. An exclusive OR operation is performed between the internal vector data V and the primary ciphertext E1 for generating a secondary ciphertext E₂.

The invention discloses a digital image encryption method based on a Cat mapping and hyper-chaos Lorenz system, and belongs to the field of image encryption. According to the digital image encryption method, a key length of an image encryption system is 247 digits and is higher than classical cryptography algorithms of the data encryption standard (DES, 56 digits), the advanced encryption standard (AES, the basic standard is 128 digits) and the international data encryption algorithm (IDEA, 128 digits). By introducing a secret key stream generative mechanism related to plaintexts, secret key streams are enabled to be related to both secret keys and the plaintexts, and even when the same diffusion secret keys are used to encrypt different plaintext images, the generated secret key streams are different. Therefore, the known-resistant/plaintext-selective attack capacity of the encryption system is obviously improved.

A stream cipher encryption method and apparatus that can efficiently seek to arbitrary location in a keystream, and a method of generating an arbitrary segment of keystream.

Provided are apparatuses, methods, and user interfaces for requesting access to a program or service, receiving the requested program or service and displaying the requested program or service at a user terminal. In one example, a request for a period of time for access to the program or service is transmitted from a user terminal via a broadcast network. The period of time may be converted to a key decryption count corresponding to the period of time and key interval, the key interval being a period of time separating adjacent key stream messages in a key stream corresponding to a content data stream for the program or service. The encrypted program or service may be decrypted at the user terminal based on the period of access, key interval, and/or key decryption count.

Methods of encrypting and decrypting data, and a bus system using the methods are provided. The method of encrypting data includes: performing an operation on data that is to be transmitted through a bus with a key stream generated from a predetermined key so as to encrypt the data; transmitting the encrypted data to a predetermined module through the bus; and transmitting a synchronization signal that is logic high when the encrypted data is transmitted through the bus to the predetermined module. Therefore, an encryption speed is improved and encryption can be simply embodied so that security of data received from the bus can be improved.

This invention discloses an encryption and decryption method for data in hardware. It consists of several steps: obtain the key by reading data from the ROM; obtain the original key by the expending mechanism; operate the logic address and the sequence number and shift the result to get the address key; encryption on the address key by the original key to form a key flow; encryption and decryption on transmitting data. This invention could enhance data security on storage device and protect them from missing.

Moving from server-attached storage to distributed storage brings new vulnerabilities in creating a secure data storage and access facility. The Data Division and Out-of-order keystream Generation technique provides a cryptographic method to protect data in the distributed storage environments. In the technique, the Treating the data as a binary bit stream, our self-encryption (SE) scheme generates a keystream by randomly extracting bits from the stream. The length of the keystream depends on the user's security requirements. The bit stream is encrypted and the ciphertext is stored on the mobile device, whereas the keystream is stored separately. This makes it computationally not feasible to recover the original data stream from the ciphertext alone.

The invention discloses a method for cryptoguard by utilization of infinite dimensional hyperchaos for construction of unilateral hash functions, wherein, a plaintext and a key are taken as initial values of two hyperchaos Chen systems provided with delay feedback at first; evolvement is performed according to characteristics of chaotic dynamics of the system; a final result of evolvement is quantized; the quantized value is substituted into key streams for iteration; confusion and diffusion of plaintext information and key information are realized, and a 128-bit Hash value of the plaintext with any length is generated on the basis of a cipher block chain mode. The method of the invention performs cryptoguard by construction of the Hash functions, fully utilizes signals generated by an infinite dimensional hyperchaos system to improve the scrambling performance of the signals and the sensitivity of parameters, and has stronger attack resistance and better safety to predicted attacks.

The invention discloses a document scrambling transmission system and a method. A transmitting terminal cuts the document to be transmitted into two parts that are an attribute description document and document content data. After the document content data is carried through slicing treatment, a cipher code flow is utilized to carry through scrambling treatment on the data slices; after the attribute description document is carried through the slicing treatment, the attribute description document slices and the data slices after being scrambled are carried through data packet sealing and then transmitted to a receiving terminal through a transmission network. Furthermore, before the slicing treatment is carried through on the attribute description document, the scrambling parameters that are not changed in the whole scrambling process are written in the attribute description document. The document transmission method and the system of the invention transmits the scrambled control words by a mode of ciphertext and transmits the document data by a scrambling data flow, thus leading the document transmission to have higher security.

Embodiments of reversible systems and methods for fast, secure and efficient transmission, storage, and protection of digital multimedia are disclosed. The embodiments may have the ability to simultaneously compress and encrypt digital data in order to concurrently reduce data size and prevent reconstruction without the proper encryption key. Embodiments of a method may include pre-processing data to optimize the size of data segments to be compressed, transforming the data for improving the compressibility of the before-mentioned data segments, processing the data sequentially to generate predictive statistical models, encoding the data for simultaneously encrypting and compressing data segments using a keystream, and increasing both the compression ratio and security of these encoding processes using a block cipher. Embodiments of these methods may be suitable for use on both encrypted and unencrypted media.

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.

The invention relates to a color image lossless encryption method on the basis of two-dimensional discrete wavelet transform and spatiotemporal chaos. The color image lossless encryption method comprises the following steps: separating three primary color components of a color plaintext image to obtain matrices IR0, IG0 and IB0; by utilizing an external key and combining the plaintext image, generating spatiotemporal chaos system parameters and initial values and carrying out iterative operation on a spatiotemporal chaos system to obtain key streams K1 and K2; carrying out two-dimensional discrete wavelet transform on the components IR0, IG0 and IB0 to obtain three groups of sub-bands; utilizing the key stream K1 to respectively carry out disorder processing on the three groups of sub-bands and compressing the sub-bands; respectively carrying out two-dimensional discrete wavelet transform on each group of processed sub-bands to obtain a wavelet encrypted image I1; utilizing the key stream K2 to carry out diffusion treatment on the image I1 to obtain a final ciphertext image C. Compared with an existing image encryption method, the color image lossless encryption method provided by the invention has the advantages of high safety, good encryption effect, lossless information, high encryption speed, high attack resistance and the like and can be widely applied to the fields of medicine, biological gene, military and the like.

The present invention provides methods, apparatuses, and systems for delivering protected multi-media content to a receiving device. Protected multi-media content and key information are inserted in a same time slice burst. Multi-media content is processed into content datagrams, in which each content datagram is associated with a corresponding component. Key information may be processed as a keystream with key datagrams or may be included in one or more components. A content datagram may be encrypted with an associated key. A receiving device receives the time slice burst with the content datagrams and the key information. The receiving device subsequently decrypts the content datagrams with the key information. Key datagrams may be associated with a higher priority level than content datagrams. Consequently, a receiving device can process a key datagram in order to extract a key before routing associated content datagrams to a message stack.

The objective of the invention is to provide a method of chaotic hybrid self-synchronization. Both communication sides get digital signal after sampling and analog-digital conversion of local continuous chaotic signal respectively at regular intervals. Sender executes pulse synchronization to continuous chaotic system with received digital signal and then transmits error correction signal including 1bit information to receiver. Receiver executes pulse synchronization to its continuous chaotic system with corrected digital signal. Continuous chaotic system at different location only need to transmit error correction information of 1bit to keep long period of steady synchronization through the synchronization method. Occupation rate to channel by redundant information fall to low and anti-attack ability of chaotic system is improved efficiently. The digital chaotic sequence output by chaotic system that synchronized through the invention can be used to encrypt data as pseudo-random sequence or key stream; the output continuous chaotic signal can be used to design encryption communication system that based on chaotic synchronization.

The invention discloses a word-oriented key stream generating method and an encrypting method. The key stream generating method comprises the steps of: generating, namely generating a source sequence and outputting the source sequence to a selecting step; selecting, namely selecting some bits in the source sequence to form four outputs, wherein three outputs are inputted to a mixing step, and another output is outputted to an outputting step; mixing, namely performing non-linear compression transformation on the three inputs to form an output; and outputting, namely receiving the output of the selecting step and the output of the mixing step and performing combined compression to obtain the key stream for outputting. The key stream sequence generated by the method has quite high randomness and non-linearity, and is much suitable to be quickly realized by software and hardware; and the encrypting method by using the key stream generated in the invention has higher security.

A cryptographically secure keystream generating process includes an expanding amorphous process. A seed key is expanded into a partition index that is carved into elements (parameters) by a parallelizable process. A dispersing value is derived from the partition index to de-cluster subsequent partition indexes. The process operates with constant entropy by “recarving” elements and employs block holdbacks for increased variance during multiplexing. Internal emissions are derived from the amorphous process itself, which provide secure random sources for subsequent use within the keystream generation process. Seed key expansion and dispersing value computation both use cyclic redundancy code evaluation employing multiple polynomials. A public (mono) base key family is defined with three preferred modes, two of which are specialized for software implementation. Two private base key embodiments are included that constantly morph the base key.

The invention discloses a digital image feedback encryption method based on an image network. The method comprises the following steps of processing a digital plaintext image; constructing the image network in which a node is a super-chaotic system and a non-neighbor connection mode is possessed; through three-dimensional Arnold, converting a scrambling image, wherein a scrambling matrix is driven by image-network space-time chaotic display and a current plaintext image; combining feedback information of the current plaintext image and a cryptograph image and carrying out image diffusion processing; alternatively operating scrambling and diffusion multiple times and acquiring the cryptograph image. In an encryption system, a scrambling-diffusion alternative-operated loop iteration structure is designed; during an encryption process, plaintext and cryptograph feedback mechanisms are introduced; and during each encryption, the used scrambling matrix and a secret key flow are dynamically changed and are different. An experiment result shows that the encryption method possesses high safety and high efficiency; and a capability of resisting various plaintext attacks, statistics attacks, violence attacks and difference attacks is high.

Methods and circuitry are disclosed for decoding a keystream. A set of test bits is generated, and a set of attempted keystream bits are generated from differences between the test bits and an input set of cipher bits. A set of current keystream bits are generated from a current seed using a parallel feedback shift register, and the attempted keystream bits are compared to the current keystream bits. In response to attempted keystream bits being equal to the current keystream bits, the current keystream bits are fed back as a new current seed. In response to attempted keystream bits being not equal to the current keystream bits, the attempted keystream bits are fed back as the new current seed.