Abstract: A method and apparatus are disclosed for generating random numbers using the meta-stable behavior of flip-flops. A flip-flop is clocked with an input that deliberately violates the setup or hold times (or both) of the flip-flop to ensure meta-stable behavior. When a meta-stable event is detected, an output bit is provided as a random bit. An even random number distribution is obtained by “marking” half of the zeroes input to the flip-flop as “ones” and the other half of the zeroes as “zeroes.” In addition, half of the ones are marked as “ones” and the other half of the ones are marked as “zeroes.” The marking signal is uncorrelated to any noise to a high probability using a linear feedback shift register.

Abstract: A copy protection system for protecting content wherein a ticket and a watermark are created, utilizing a first time reference (TD) and a one-way function, to indicate the copy protection status of the content. A source device produces the ticket and watermark using a first time reference and a hashing function. The source device provides a data stream containing the content, the ticket, the watermark, and the first time reference (TD) to the receiver device. The receiver device determines if the first time reference (TD) is contained within a time window determined by a second time reference. When, the first time reference (TD) is contained within the time window, the receiver compares the ticket to the watermark using the first time reference (TD) and the one-way function, and based on the comparison, produces a signal indicating the copy protection status of the content.

Abstract: Methods and apparatus for verifying the presence of original data in content. The method includes the steps of collecting data associated with the content, evaluating the collected data to verify the presence of original data in the content, and rejecting the content if a number of errors detected during the evaluating step exceeds a threshold number of errors. Certain aspects of the method may vary depending on whether the content is analog or digital. In an illustrative embodiment, a determination is made as to a number of sections of content to evaluate. This determination is preferably a function of a desired level of security. Each of the sections includes a watermark embedded therein which uniquely identifies a corresponding section and contains information which may be used to verify the presence of original data in the content. If the information does not verify correctly, an error counter is incremented.

Abstract: A method of verifying the presence of original data in content while copying the identifiable subset within the content. The method includes the steps of accessing at least the identifiable subset within the content, collecting at least one set of data contained within the content, and evaluating the at least one set of data to verify the presence of original data in the identifiable subset and the content. The collecting step may collect a first set of data, wherein the first set of data is contained within the identifiable subset, and a second set of data, wherein the second set of data is contained within the entire content. In that case each of the first and second sets of data is evaluated to verify the presence of original data in the identifiable subset and the content. Additionally, certain aspects of the method may vary depending on whether the content is analog or digital.

Abstract: A copy protection system for protecting content wherein a ticket and a watermark are created, utilizing a first time reference (TD) and a one-way function, to indicate the copy protection status of the content. A source device produces the ticket and watermark using a first time reference and a hashing function. The source device provides a data stream containing the content, the ticket, the watermark, and the first time reference (TD) to the receiver device. The receiver device determines if the first time reference (TD) is contained within a time window determined by a second time reference. When, the first time reference (TD) is contained within the time window, the receiver compares the ticket to the watermark using the first time reference (TD) and the one-way function, and based on the comparison, produces a signal indicating the copy protection status of the content.

Abstract: Methods and apparatus for attacking a screening algorithm. The methods include the steps of searching a medium to determine a location of at least one sample stored on the medium, and applying the sample to content, wherein the content would not pass the screening algorithm but for the application of the sample. Once the locations of the samples are known, the attacker can use the samples to distribute a compressed version of the disk or a song contained on the disk from which the samples are derived, use the samples to import any disk into the SDMI domain, or use the samples to smuggle pirated music into the SDMI domain.

Abstract: Methods and apparatus for preventing an attack on a screening algorithm. A method includes the steps of identifying content to be downloaded, determining a total number of sections of a predetermined duration of time in the content to be downloaded, and screening a predetermined number of sections of the total number of sections to determine whether the predetermined number of sections verify correctly through the screening algorithm. The number of predetermined sections screened during the screening step of the method of preventing an attack on a screening algorithm is two for content having a duration of three minutes or less and is incremented by one for each one minute of duration over the initial three minutes.

Abstract: Apparatus and methods for detecting illicit content that has been imported into a secure domain, thereby preventing an attack on a screening algorithm. A method of preventing an attack on a screening algorithm includes the steps of determining whether content submitted to a screening algorithm contains indicia indicating that the content is protected, admitting the content into a segregated location of a secure domain if it is determined that the content does not contain indicia indicating that the content is protected, and monitoring the content within the segregated location to detect whether any editing activity is performed on the content. The content is admitted into the segregated location only when it is determined that the content does not contain indicia indicating that the content is protected. The method also includes the step of determining whether the edited content contains indicia indicating that the content is protected, after editing activity is detected.

Abstract: Methods and apparatus for attacking a screening algorithm. The methods include the steps of marking content to be downloaded, inserting at least one section of legitimate content into the marked content, and subjecting the content to a screening algorithm. The screening algorithm may include the steps of determining a number of segments that are included within the content, selecting at least two segments within the content, screening the two segments to determine whether the two segments verify correctly through the screening algorithm, and downloading the content when it is determined that the two segments verify correctly through the screening algorithm. Once the content has been successfully downloaded, the integrity of the downloaded content may be restored by removing the legitimate content that was previously inserted into the downloaded content.

Abstract: A digital signature of a document is formed in a digital signing device by using a private key stored in the digital signing device. A number of data items are supplied to the signing device. The signing device uses the data items to derive and authenticate a document hash. The digital signature is only formed if the derived document hash is authenticated.

Abstract: In a public key cryptosystem employing the El-Gamal algorithm, secret fresh random numbers are generated at a server and private keys of users, as encrypted with a symmetric algorithm by using individual user identifying keys determined by hashing the users' respective passphrases or biometric information (fingerprint, voiceprint, retina scan, or face scan) are maintained in a store accessible to the server, and the fresh random numbers and encrypted private keys are transmitted to the user equipment when needed via a network which is not secure. In order to prevent an attacker from discovering the random numbers or employing formerly used random numbers in a block replay attack, an interchange in the nature of a challenge response protocol is employed which passes at least one secret fresh random number from the server to the user equipment while also authenticating the user to the server.

Abstract: A method for secure anonymous querying by a user of an information provider by electronic mail and for obtaining a reply uses a public key of the provider to form an electronic encrypted query package containing information including a query, a generated random number sequence, a hash of the query, a generated public key of the user, and an identification of a public bulletin board. The query package is preferably sent to the provider via a network from a public terminal. At the information provider the query package is received and decrypted. If the result of hashing the decrypted query is equal to the decrypted hash, a response R is formulated. A response package is formed therefrom by using a generated symmetric key of the information provider and the public key of the user. The response package is posted to the public bulletin board along with the random number sequence.

Abstract: Video display apparatus having multiple processors for operation in parallel, each processing a respective complete video image in the sequence of video images (fields or frames) which form a video picture, the processing being in accordance with a selected signal processing algorithm. The algorithm may be one which simulates a signal processing circuit design which is to be evaluated, so that the effect of changes in circuit design can be displayed in real time. The signal data for each of the sequential video images is assembled into data packets in successive equal time slots, which are transmitted downstream on a data bus along which are a succession of data processors. The headers of the packets for a given image identify a serially corresponding processor to which such image is assigned, and such packets are processed by the assigned processor in accordance with the selected algorithm.

Abstract: A Multiple Instruction Stream Multiple Data Stream (MIMD) parallel processing apparatus and compiling method for effectuating collective branching of execution by the processors includes specialized branch and fuzzy barrier units which operate with respect to special instructions scheduled in unshaded regions of the instruction streams of the processors involved in a collective branch. A special compare instruction is scheduled in a first unshaded region of only one of the processors while a special jump instruction is scheduled in the next unshaded region of the instruction stream of the other involved processors. By the special jump instruction, the other processors use the special compare result which is simultaneously passed to each of them by the branch unit for determining the execution branch. The barrier unit provides fuzzy barrier synchronization assuring that the correct compare result is used in this determination.