Abstract: A method for content access control operative to enable authorized devices to access protected content and to prevent unauthorized devices from accessing protected content, the method comprising: providing a plurality of authorized devices; dividing the plurality of authorized devices into a plurality of groups, each of the plurality of authorized devices being comprised in at least one of the plurality of groups, no two devices of the plurality of authorized devices being comprised in exactly the same groups; determining whether at least one device of the plurality of authorized devices is to be prevented from having access to the protected content and, if at least one device is to be prevented, removing all groups comprising the at least one device from the plurality of groups, thus producing a set of remaining groups; and determining an authorized set comprising groups from the set of remaining groups, such that each device of the plurality of authorized devices which was not determined, in the determining

Abstract: A method for preventing cloning of a genuine security element is described. The method includes associating a random number generator (RNG) in the security element with a portion of a non-volatile memory (NVM) in the security element, and activating the RNG to automatically write, during a normal operation mode of the security element, a new random number into the portion of the NVM whenever an attempt is made to write into the portion of the NVM. Any unit other than the RNG is preferably prevented from writing data into the portion of the NVM during the normal operation mode of the security element. Related apparatus and method are also described.

Abstract: A method for producing a certificate, the certificate including data, the method including choosing a seed s, the seed s including a result of applying a function H to the data, generating a key pair (E,D), such that E=F(s,t), F being a publicly known function, and including s and t in the certificate. Related methods, and certificates produced by the various methods, are also described.

Abstract: A method and apparatus for transferring electronic content. The method and apparatus include providing electronic content to a first user, providing the first user with a key packet, the key packet including a decryption key and content rights information, transferring the electronic content and the key packet from the first user to a second user and rendering rights of the first user to the electronic content unusable upon transfer of the electronic content and the key packet from the first user to the second user.

Abstract: A system and a method for the creation and transmission of “pre-encrypted” digital content, which is encrypted before being placed on a distributed media transmission server. Preferably a plurality of such servers are used, for example in order to be able to place such a media transmission server in physical proximity to the end user client, whether in terms of geographical proximity or proximity through the network. Use of a plurality of transmission servers also optionally enables the media content to be transmitted flexibly, according to the request of the end user through the end user client.

Abstract: A method for content access control operative to enable authorized devices to access protected content and to prevent unauthorized devices from accessing protected content, the method comprising: providing a plurality of authorized devices; dividing the plurality of authorized devices into a plurality of groups, each of the plurality of authorized devices being comprised in at least one of the plurality of groups, no two devices of the plurality of authorized devices being comprised in exactly the same groups; determining whether at least one device of the plurality of authorized devices is to be prevented from having access to the protected content and, if at least one device is to be prevented, removing all groups comprising the at least one device from the plurality of groups, thus producing a set of remaining groups; and determining an authorized set comprising groups from the set of remaining groups, such that each device of the plurality of authorized devices which was not determined, in the determining

Abstract: A method for content access control operative to enable authorized devices to access protected content and to prevent unauthorized devices from accessing protected content, the method comprising: providing a plurality of authorized devices; dividing the plurality of authorized devices into a plurality of groups, each of the plurality of authorized devices being comprised in at least one of the plurality of groups, no two devices of the plurality of authorized devices being comprised in exactly the same groups; determining whether at least one device of the plurality of authorized devices is to be prevented from having access to the protected content and, if at least one device is to be prevented, removing all groups comprising the at least one device from the plurality of groups, thus producing a set of remaining groups; and determining an authorized set comprising groups from the set of remaining groups, such that each device of the plurality of authorized devices which was not determined, in the determining

Abstract: An access control method for use with a broadcast communication network is described. The access control method includes the steps of receiving an encoded program at a subscriber unit via the broadcast communication network, and preventing decoding of the encoded program at the subscriber unit for at least one preselected time period, preselected in accordance with a preference of a user of the subscriber unit. Alternatively, the encoded program received at the subscriber unit may be decoded for at least one preselected time period, preselected in accordance with a preference of the user of the subscriber unit. Related methods and apparatus are also described.

Abstract: A communication session management method for providing a transmission service having a plurality of service-levels, each service-level being associated with a separate quality-of-service (QOS), the method including preparing data for transmission at one of the plurality of service-levels by uniquely associating a service-level encryption key with the one of the plurality of service-levels, encrypting the data with the service-level encryption key to form encrypted data uniquely associated with the one of the plurality of service-levels, and transmitting the encrypted data uniquely associated with the one of the plurality of service-levels to users entitled to the one of the plurality of service-levels.

Abstract: In a method for verifying, by a verifier, that a prover has access to a private key associated with a public key Kp, in which the method comprises the prover generating a random number R and communicating a disguised form of the random number R to the verifier, an improvement including the prover generating the random number R based on an input received from the verifier. Related apparatus and methods are also provided.

Abstract: A method for content access control operative to enable authorized devices to access protected content and to prevent unauthorized devices from accessing protected content, the method comprising: providing a plurality of authorized devices; dividing the plurality of authorized devices into a plurality of groups, each of the plurality of authorized devices being comprised in at least one of the plurality of groups, no two devices of the plurality of authorized devices being comprised in exactly the same groups; determining whether at least one device of the plurality of authorized devices is to be prevented from having access to the protected content and, if at least one device is to be prevented, removing all groups comprising the at least one device from the plurality of groups, thus producing a set of remaining groups; and determining an authorized set comprising groups from the set of remaining groups, such that each device of the plurality of authorized devices which was not determined, in the determining

Abstract: A method for determining that all of a scrambled message has been successfully received, the scrambled message being scrambled in accordance with a scrambling key and being capable of being descrambled in accordance with a descrambling key, descrambling key generating information for generating the descrambling key being included within a control message (ECM) associated with the scrambled message.

Abstract: A key delivery method for use in an encoded communications system in which at least one encoded item including a first item encoded with a first item control word is sent in a communication stream from a sender to a receiver, the method including transmitting an item entitlement control message (IECM) including item control information, transmitting a stream entitlement control message (SECM) including stream control information, and combining at least part of the item control information and at least part of the stream control information to produce the first item control word. Related methods and apparatus are also disclosed.

Abstract: The invention concerns a method and apparatus to synthesize a frequency employing digital phase words to represent successive phase values. A digital dither signal generator is used to generate a succession of dither words which are summed with the phase words to form address words. The address words are used to address a store to convert the address words to waveform values. The periodic quantisation noise introduced by the digital process is made more random by means of the dither words thereby reducing the quantisation noise components while accepting an increased total noise power. The synthesizer is of particular advantage when used to generate the reference frequency for a frequency multiplier implemented as a phase lock loop. By making the dither sequence repetition frequency outside the phase lock loop bandwidth, the spurious components are removed from the frequency range of interest.

Abstract: This invention discloses a vehicle theft prevention system which is operative to communicate with a central control station that transmits control signals to the vehicle, the system including an antenna, a receiving unit coupled to the antenna and operative to receive, via the antenna, the control signals transmitted by the central control station, and a processor which is operative to apply interference to operation of at least one critical engine component in the vehicle after an interruption in reception of the control signals at the receiving unit. A method of preventing a theft of a vehicle is also disclosed.