Method of Controlling Access to a Scrambled Content
AssigneeVaccess
InventorsAnthony Chevallier, Stephane Lanfranchi, Erwann Magis
Life of this patent
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Abstract
A method for access control to a digital scrambled content distributed to a set of installed reception terminals including one master terminal and at least one slave terminal dependent on the master terminal. In the method the slave terminal systematically or occasionally returns at least one item of information about the access condition to the master terminal through a point-to-point link, to enable the master terminal to control access of the slave terminal to the content.
Claims46
1-51. (canceled)
A method for access control to a scrambled content supplied by an operator to a reception terminal with which an access management unit is associated, the terminal including at least one access control module, the method comprising:
- associating an access condition with the content including a plurality of information necessary for descrambling the content;
- transmitting the content with the access condition to the terminal;
- on reception of the access condition by the terminal,
- systematically or occasionally sending at least one item of information about the access condition from the terminal to the access management unit through a point-to-point link, and
- processing the information by the access management unit to enable or prevent use of the content by the reception terminal depending on a result of the processing.
An access control system comprising:
- an emission device including a content server;
- an access management unit associated with the emission device;
- a reception terminal including at least one access control module controlling access to a scrambled content supplied by the content server and with which an access condition is associated including a plurality of information necessary for descrambling the content,
- wherein the reception terminal is connected to the access management unit through a point-to-point link through which the access control module systematically or occasionally returns at least one item of the information about the access condition to the access management unit so as to enable the access management unit to process the information to enable or prevent use of the content by the reception terminal depending on the result of the processing performed by the access management unit.
A distribution device for distributing a transmitted scrambled content, with an access condition including a plurality of information necessary for descrambling the content, to at least one reception terminal including an access control module, associated with an access management unit communicating with the access control module of the reception terminal through a point-to-point link.
A reception terminal for receiving a scrambled content distributed by a content distribution device associated with an access management unit, the terminal comprising:
- at least one access control module communicating with the access management unit through a point-to-point link.
A computer program designed to implement an access control method controlling access to a scrambled content supplied by an operator, with which an access management unit is associated, at a reception terminal including an access control module, the computer program comprising:
- a first module stored in the terminal comprising instructions to systematically or occasionally forward at least one item of information of the access condition from the terminal to the access management unit through a point-to-point link, the first module cooperating with a second module stored in the access management unit comprising instructions to process the information and instructions to enable or prevent use of the content by the reception terminal depending on the result of the processing.
A method for controlling access to a scrambled content distributed to a set of installed reception terminals including one master terminal and at least one slave terminal dependent on the master terminal, the method comprising:
- associating an access condition with the content, including a plurality of information necessary to descramble the distributed content;
- assigning a common session key KS to the master and slave terminals;
- transmitting a datastream to terminals in the set of installed terminals including the scrambled digital content and the access condition;
- on reception of the datastream, the slave terminal extracting the access condition from the received datastream and systematically or occasionally returning at least one item of information about the access condition to the master terminal through a point-to-point link set up with the master terminal;
- and
- on reception of the information forwarded by the slave terminal, the master terminal verifying if the information is compatible with access rights previously allocated to the slave terminal, and returning at least one command parameter to the slave terminal, encrypted by the session key Ks authorizing use of the content if the information is compatible with the access rights, or preventing use of the content if the information is not compatible with the access rights.
An access control system comprising:
- an emission device including one content server;
- one master terminal;
- at least one slave terminal dependent on the master terminal;
- the content server including means for distributing a scrambled digital content with which an access condition is associated including a plurality of information necessary for descrambling the content, to the terminals,
- wherein the slave terminal can be connected to the master terminal through a point-to-point link through which the slave terminal systematically or occasionally returns at least one item of information extracted from the access condition to the master terminal so as to enable the master terminal to process the information to enable or prevent use of the content by the slave terminal.
A master reception terminal associated with at least one slave reception terminal in a system for distributing a scrambled content, comprising:
- a software capable of processing information transmitted by the slave terminal to enable or prevent use of the content by the slave terminal.
A computer program designed to implement an access control method controlling access to a scrambled content distributed to a set of installed reception terminals including one master terminal and at least one slave terminal, access to the content being subject to an access condition including at least one access criterion and a plurality of information necessary to descramble the content, the computer program comprising:
- a first module stored in the slave terminal including instructions to extract the access condition from the received datastream, and systematically or occasionally forward at least one item of information about the access condition to the master terminal, through a point-to-point link set up with the master terminal, the first module cooperating with a second module stored in the master terminal including instructions to process the information and instructions to enable or prevent use of the content by the slave terminal depending on the result of the processing.
A method for access control to a content supplied to a reception terminal by an operator, with which an access management unit is associated, the method comprising:
- a conditioning phase of the content by the operator and a usage phase of the content by the terminal;
- wherein the terminal is configured to store three doublets composed of a current key Kc and data Dc related to the key, a previous key Kp and data Dp related to the previous key, and a next key Ks and data Ds related to the next key respectively,
- wherein the conditioning phase comprises:
- a) breaking down a duration of the content into N time segments each being associated with one identifier Sj, one key Kj and one item of data Dj related to the key, each segment Sj including an integer number Mj of crypto-periods CPi, i=1 to Mj and j=1 to N,
- b) scrambling the content using a sequence of control words CWi,j,
- c) encrypting each control word CWi,j using the Kj key, and
- d) transmitting the scrambled content to the terminal during each crypto-period CPi, with an ECM message comprising at least the encrypted control word CWi,j, the data D related to the current key Kj, the data Dj−1 related to the previous key Kj−1, and the data Dj+1 related to the next key Kj+1, to decrypt the content during a given time segment Sj;
- and
- the usage phase comprises, on reception of the ECM message:
- e) the terminal analyzing data Dj contained in the message;
- and
- f) if data Dj contained in the ECM message corresponds to the data Dc previously stored in the terminal, the terminal decrypting the control word CWi,j with the key Kc associated with the data Dc,
- g) if the data Dj contained in the ECM message corresponds to the data Dp previously stored in the terminal, the terminal decrypting the control word CWi,j using the key Kp, and if the data Dj corresponds to the data Ds, the terminal decrypts the control word CWi,j using the key Ks, and
- h) if the data Dj contained in the ECM message does not correspond to the data Dc, previously stored in the terminal, the terminal sending the received ECM message to the access management unit that determines the current key Kj from the data Dj, the previous key Kj−1 from the data Dj−1 and the next key Kj+1 from the data Dj+1, and sending the keys and their related data to the terminal that stores their corresponding values as new values of the keys Kc, Kp and Ks and data Dc, Dp et Ds related to these keys.
A method for access control to a scrambled content distributed by an operator to a set of installed reception terminals including one master terminal and at least one slave terminal dependent on the master terminal, the method comprising:
- a conditioning phase of the content by the operator;
- and
- a usage phase of the content by the slave terminal;
- wherein the slave terminal is configured to store three doublets composed of a current key Kc, and data Dc related to this key, previous key Kp and related data Dp, and a next key Ks and related data Ds respectively,
- the conditioning phase comprising:
- a) breaking down a duration of the content into N time segments each being associated with one identifier Sj, one key Kj and one item of data Dj related to the key, each segment Sj including an integer number Mj of crypto-periods CPi,
- and for i=1 to Mj and j=1 to N,
- b) scrambling the content using a sequence of control words CWi,j,
- c) encrypting each control word CWi,j using the Kj key, and
- d) transmitting the scrambled content to the slave terminal during each crypto-period CPi, with an ECM message comprising at least the control word CWi,j, the data Dj related to the current key Kj, the data Dj−1 related to the previous key Kj−1, and the data Dj+1 related to the next key Kj+1, to decrypt the content during a given time segment Sj;
- and
- the usage phase comprises, on reception of the ECM message:
- e) the slave terminal analyzing data Dj contained in the message, and
- f) if data Dj contained in the ECM message corresponds to the data Dc previously stored in the slave terminal, the slave terminal decrypting the control words CWi,j with the key Kc associated with the data Dc,
- g) if the slave data Dj contained in the ECM message corresponds to the data Dp, previously stored in the slave terminal, the slave terminal decrypting the control word CWi,j using the key Kp related to data Dp, and if the slave data Dj corresponds to data Ds, the terminal decrypting the control word CWi,j using the key Ks, related to data Ds, and
- h) if the slave data Dj contained in the ECM message does not correspond to the data Dc previously stored in the slave terminal, the slave terminal sending the received ECM message to the master terminal that determines the current key Kj from the data Dj, the previous key Kj−1 from the data Dj−1 and the next key Kj+1 from the Dj+1, and sending the keys and their related data to the slave terminal that storing their corresponding values as new values of the keys Kc, Kp and Ks and data Dc, Dp et Ds related to these keys.
Dependencies are inferred from the claim text.