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EP0492486A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Systems and devices for the cryptography of digital signals

Assignee: Alcatel Lucent Italia SpA
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Filing: 1991-12-20
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Granted: —
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Expires: 2011-12-20
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Abstract

Abstract A system for managing safety characteristics in an audio or video service network is particularly adapted to allow only authorized receivers to receive transmitted signals correctly. To this end, the signals to be transmitted in digital form are encoded, the digital information leaving the encoding stage is cryptographed in using a key k, and both the key and the information referring to the decoding algorithm are sent to the authorized receivers in secret form. At the receiving side, the key k received from the transmitter is decoded and then, the digital signal received is decoded in using the specified algorithm and the decoded key k.

Inventors

  • 👤 Silvio Cucchi
  • 👤 Giorgio Parladori
  • 👤 Roberto Maestri

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-30 12:15
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/167; H04N21/00; H04N21/20; H04N21/25; H04N21/254; H04N21/2541; H04N21/266; H04N21/26613; H04N7/1675

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 131 words
A system for the management of the safety characteristics in a audio and video service network, in particular for allowing to the sole authorized receivers to get a right reception of the transmitted signals, characterized in that it includes at least the following stages: in transmission: 1a to encode the signals to be transmitted in digital form; 1b to cryptograph the digital information outgoing from said encoding stage using a key k 1c to send said key k and the information referring to the decoding algorithm in secret form to the authorized receivers; in reception: 1d to decode the above mentioned key k sent from the transmitter; 1e to decode said digital signal received using the specified algorithm and the key k of 1c and, 1f to decode the received signals.
Claim 2
Dependent Claim 26 words
A system according to claim 1, in which it is used the public key technics to carry out the stages specified in paragraphs 1c and 1d.
Claim 3
Dependent Claim 37 words
A system according to claim 1, characterized in that it is used the DES algorithm and contemporaneously or as alternative solution it is used the synchronous scramblering technics for implementing the stages of paragraphs 1b and 1c.
Claim 4
Dependent Claim 29 words
A system according to claim 1, in which a slow channel, preferably inserted in the transmission frame, and a protocol for the management of the described mechanisms are used.
Claim 5
Independent Claim 9 words
A system substantially according to what described and represented.

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