摘要:
Multimedia content or related data is securely transferred between a source device and a sink device in a secure multimedia content delivery device, such as a set-top box, using keys modified by logically combining them with copy control-related bits associated with the data.
摘要:
A secure Internet Protocol (IP) telephony system, apparatus, and methods are disclosed. Communications over an IP telephony system can be secured by securing communications to and from a Cable Telephony Adapter (CTA). The system can include one or more CTAs, network servers, servers configured as signaling controllers, key distribution centers (KDC), and can include gateways that couple the IP telephony system to a Public Switched Telephone Network (PSTN). Each CTA can be configured as secure hardware and can be configured with multiple encryption keys that are used to communicate signaling or bearer channel communications. The KDC can be configured to periodically distribute symmetric encryption keys to secure communications between devices that have been provisioned to operate in the system and signaling controllers. The secure devices, such as the CTA, can communicate with other secure devices by establishing signaling and bearer channels that are encrypted with session specific symmetric keys derived from a symmetric key distributed by a signaling controller.
摘要:
A method and apparatus are provided for communicating VBI user information for digital television. A syntax is provided which allows the transport of closed captions, non-realtime video, sampled video and AMOL. Non-realtime video can be used to transport various types of data, such as a vertical interval test signal (VITS) through the system at full resolution. The provision in the syntax of a count for each type of VBI user information enables the adjustment of a digital television data stream to accommodate variable amounts and types of such information without space being reserved in advance. The provision of a priority number in the syntax enables decoders to discard VBI user information priorities which are not supported by the particular decoder.
摘要:
A method and apparatus are provided for communicating VBI user information for digital television. A syntax is provided which allows the transport of closed captions, non-realtime video, sampled video and AMOL. Non-realtime video can be used to transport various types of data, such as a vertical interval test signal (VITS) through the system at full resolution. The provision in the syntax of a count for each type of VBI user information enables the adjustment of a digital television data stream to accommodate variable amounts and types of such information without space being reserved in advance. The provision of a priority number in the syntax enables decoders to discard VBI user information priorities which are not supported by the particular decoder.
摘要:
Apparatus is provided for authenticating information using a double feedforward hash function to provide complementarity in the implementation of an encryption algorithm. A cryptographic processor has a first input for receiving plaintext, a second input for receiving a key and an output for outputting ciphertext generated by cryptographically processing the plaintext and key. A first circuit element is responsive to the ciphertext and plaintext for outputting a first ciphertext derivative. A second circuit element is responsive to at least a portion of the first ciphertext derivative and the key for outputting a second ciphertext derivative. The first and second circuit elements can be XOR gates. Alternatively, these elements can be provided using lookup tables. Subsequent cryptographic processor stages can be provided having a first input for receiving second plaintext, a second input for receiving the second ciphertext derivative as a key, and an output for outputting second ciphertext generated by cryptographically processing the second plaintext and the second ciphertext derivative. In an illustrated embodiment, the cryptographic processor is a DES processor.
摘要:
A video decompression processor acquires video data for a desired service from a packetized data stream. The data stream includes transport packets carrying different components of the desired service. Each component is identified by a unique packet identifier (PID). One of the components includes a program clock reference (PCR) providing timing information for the desired service. The PIDs of the transport packets are monitored to recover video packets. Header information from the recovered packets is processed to recover packetized elementary stream (PES) packets having a PES header and picture information. Time stamp information obtained from the PES header is appended to the picture information for storage in a video memory. Picture information can subsequently be read from the memory and decoded using the appended time stamp information without having to reaccess the PES header. Various schemes for detecting, masking and recovering from transmission errors are disclosed.
摘要:
Incremental delivery of authenticated access rights to an access control processor is provided. Subgroups of the access rights are communicated to the processor in a plurality of messages. The subgroups are stored in different data banks within the processor, and validity designations associated with the data banks indicate whether the data currently stored therein has been authenticated under a cryptographic key currently in use. Access under a particular key is limited to that provided by access rights contained in storage banks having a validity designation in a valid state for that key.
摘要:
Alignment of an antenna and a polarizer for the antenna are automatically adjusted and the frequency setting of a frequency-tunable receiver is automatically adjusted while receiving a broadcast communication signal that is forward-error-correction coded by processing the forward-error-correction code of the received signal to measure a channel-bit-error-rate-affected parameter for the received signal; by realigning the antenna and the polarizer from their respective initial positions in response to the measured parameter until the measured parameter is minimized; and by retuning the receiver from its initial frequency setting in response to the measured parameter unitl the measured parameter is minimized. A Viterbi decoder processes the forward-error-correction code of the received signal to compute path metrics affected the bit-error rate of the received signal and normalizes the computed path metrics; and a counter counts the normalizations over fixed intervals to measure a path metric normalization rate as the measured parameter.
摘要:
A block-cipher cryptographic device that processes plaintext/encrypted input data with a key signal to provide encrypted/decrypoted output data. Such device includes a shift register for receiving input data; and data processing means for executing the following data processing routine a selected number of cycles to provide output data: processing the contents of said shift register with a key signal to provide initially processed data; initializing a pseudorandom nonlinear sequence generator with the initially processed data; running the pseudorandom nonlinear sequence generator to generate a keystream; segregating portions of the keystream; processing said segregated portions of said keystream with a portion of the data in the shift register to provide a block of processed data; and shifting said block of processed data into the shift register. To further increase the randomness of the pseudorandom keystream generator, and hence the encryption security, the processing means segretates the keystream in accordance with a routine wherein the beginning of said segregated portion is provided at a time related to the beginning of the keystream in response to a duration indication; segregates every nth bit of the keystream from said beginning of said segregated portion for a selected number of segregated bits in response to a frequency indication; and provides said initially processed data by first processing said shift register contents and said key signal and then rotating data produced by said first processing in response to a rotation indication. The duration indication, the frequency indication and the rotation indication are each separately provided for each of the cycles and may be different for each of the cycles.