Philips Electronics North America Corporation

U.S. Philips Corporation

Koninklijke Philips Corporation N.v.

David W Cuccia

Michael A Epstein

Michael S Pasieka

A method and device for providing instant replay in an MPEG video decoder. The method and device provides non-MPEG frame tags for correlation of the frames in the decompressed domain to the frames in the compressed domain.

Instant replay of digital video optimized using non MPEG frame tags

The invention relates to a receiving apparatus comprising a receiver for receiving signals, e.g. radio or television signals, which comprises means for collecting particular information incorporated in at least a part of the signals, e.g. in order to build a compound electronic program guide. The apparatus according to the invention is adapted to perform the scanning when the receiver is not in use, e.g. during stand-by mode, or when the apparatus is performing a function which does not involve the receiver.

Apparatus for receiving signals during power-off (stand-by) mode

A decoding system and method for a plurality of transport streams, such as MPEG-2 encoded data streams, in which, in addition to a transport decoder, a predecoder is provided for extracting program specific information (PSI) from the plurality of transport streams. Consequently, in the event of a channel change requiring a different transport stream to be decoded, the PSI is made immediately available to the transport decoder eliminating the delay of waiting for applicable packets in the transport stream to extract the PSI prior to decoding and presenting a program to a user. A fully populated crossbar switch controlled by a micro-controller is used to feed a selected transport stream to the transport decoder and to cause the plurality of transport streams to be successively fed to the predecoder. The extracted PSI may also used by the channel mapping function of the decoding system to maintain a map of channels and associated PSI for the entire plurality of transport streams accessible by the decoding system.

Fast extraction of program specific information from multiple transport

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. In this interchange, a first random number to be distributed to the user for use in signing a document and a second random number which is to be used by the user in forming a signature of a hashing together of the first and second random numbers as part of the challenge response protocol, are supplied to the user equipment in encrypted form together with a freshness value, and a signature by the server of a hashing together of the first and second random numbers and the freshness value.

Administration and utilization of secret fresh random numbers in a

A method for providing a secure interface between a decryption engine and a system decoder of a digital receiver, e.g., an MPEG-2 digital television receiver. The system decoder receives an encrypted bitstream and produces a cipher text bitstream which is supplied to the decryption engine via a first parallel data bus which includes a plurality N of parallel bit lines corresponding to respective N bits of the cipher text bitstream. The decryption engine decrypts the cipher text bitstream and produces a plain text bitstream which is supplied to the system decoder via a second parallel data bus which includes a plurality N of parallel bit lines corresponding to respective N bits of the plain text bitstream. The method includes the steps of scrambling the bit order of the N bits of the cipher text bitstream on the respective N bit lines of the first data bus, to thereby produce a scrambled cipher text bitstream N-bits wide, descrambling the bit order of the N bits of the scrambled cipher text bitstream, to thereby produce a descrambled cipher text bitstream which is the same as the original cipher text bitstream, employing the decryption engine to decrypt the descrambled cipher text bitstream, to thereby produce the plain text bitstream, scrambling the bit order of the N bits of the plain text bitstream on the respective N bit lines of the second data bus, to thereby produce a scrambled plain text bitstream N-bits wide, and descrambling the bit order of the N bits of the scrambled plain text bitstream, to thereby produce a descrambled plain text bitstream which is the same as the original plain text bitstream. A digital receiver which implements this method is also disclosed.

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Hopewell Junction, NY, United States of America

David W Cuccia