Ravisent Technologies, Inc.

Other

Sonic Solutions

Lee Capital LLC

Randy Langer

Robert M Wolff

A method and system for authorizing client devices to receive secured data streams through the use of digital certificates embedded in the client devices. A freely distributed cryptographically signed group file with an embedded expiration date is associated with each individual digital certificate. A single group file can be associated with more than one digital certificate but each digital certificate is associated with a single group file. The group file contains cryptographic keys that can be used to decrypt a section of the digital certificate revealing a set of client keys. The client keys are then used to encrypt a program key which are then sent back to the client device. When the client device requests a specific data stream or digital content, an issuance timestamp associated with the content is compared to the expiration date in the group file. If the issuance timestamp is after the expiration date, the client device is declined. If the issuance timestamp is before the expiration date, the requested content, encrypted utilizing the program key, is sent to the client device.

Method and system for authorizing client devices to receive secured data streams

A given software process is composed on one or more threads of execution. Each thread possesses its own stack, a region of memory set aside by the operating system for that thread to store data. Popular programming languages rely heavily on stack-based data (frequently referred to as 'local' or 'automatic' data). It is a characteristic of deterministic machines like computers that, given the same problem to process with the same data, the same results, both intermediate and final, will result. This even extends to the sequence the software running on the computer will take to process the problem or data. This in turn means that for each thread making up the program, the data layout in the thread's stack will be relatively consistent each time the program gets to a similar point in the processing of the problem and/or data. This represents a potential &#x201c;point of repeatability&#x201d; that a hacker can take advantage of. Embodiments of the current invention address this by introducing random amounts of &#x201c;padding&#x201d; into a thread's stack, such that all data objects that exist &#x201c;below&#x201d; that point in the stack are offset by the amount of this random padding. A thread could have several points in its stack where the padding is introduced, resulting in better (more difficult to hack) randomization.

Deterring reverse-engineering of software systems by randomizing the siting of stack-based data

A word wise search is performed on an MPEG-2 stream. For every word, the invention finds word-aligned patterns of 0&times;00 0&times;00 or 0&times;00 0&times;01. The algorithm applied by the invention examines the input stream buffer for the first word aligned 0 in which further testing determines is the first byte of a valid start code, and sets the sub-buffer defined by the start of the search to the location of this discovered start-code as the zero-word reach. A second search is performed in the same part of the input stream buffer, this time looking for word aligned 1's (i.e. byte pattern 0&times;00 0&times;01). For each word aligned 1 that is a start code, an entry is made into a start code list. When all of these have been found, the offset of the start code ending the current zero-word reach is added to the list of start-code offsets. This process is repeated from the 0 word reach until the end of the buffer is encountered. If 0's are not word aligned, the start codes are found on the 1's search, otherwise the start codes are found on the first search.

High-speed start code scanner for MPEG-2 data streams

A method and apparatus for optimal handling of high bandwidth streaming data in a computer system minimizes computational activities to achieve maximal performance. This performance improvement is accomplished by minimizing the amount of memory copying and also by minimizing the number of allocation and deallocations of objects which occur. Memory copying is a CPU/bandwidth intense operation when there is high speed streaming data on the input. The allocation and deallocation of objects is a system resource intense activity and requires a very significant amount of CPU processing per invocation in a computing device. Using a combination of techniques, the invention provides a technique that reduces both the number of memory copies as well as the number of objects which get allocated and deallocated during the course of operating on the streaming media data.

Growing community of inventors

Port Orchard, WA, United States of America

Randy Langer