Invoicing management method of a service transmitted per time unit
AssigneeNagraCard S.A.
InventorsJimmy Cochard, Henri Kudelski, Marco Sasselli
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Abstract
The objective of the present invention is to propose an accounting method of the consumption of transmitted services per time unit to a decoder in a system implementing a content encrypted by control words, the latter being modified according to a period named crypto-period. This method consists in verifying if the time-current (TC) is comprised in a time variable (Rdate) representative of the authorisation time of use of the service and, if this is the case, decrypting and returning the control words to the decoder, and if it is not the case, debiting an amount (CT) corresponding to a time of use (AT) and recharging the time variable (Rdate) with a corresponding time.
Claims7
A time accounting method of access to a stream of data encrypted by control words (CW) modified at intervals representing a crypto-period (CP), said stream being received by a user unit (UU) linked to a security module (SC) in charge of verifying the rights of a user and of decrypting messages (ECM) comprising the control words (CW), said accounting being based on accounting units (CT) authorising the use of the service for an assigned time (AT), said method comprising the following stages:
- a. commutation by the user on an encrypted stream constituting an access service per time unit,
- b. reception by the security module (SC) of encrypted messages (ECM) containing the control words (CW) and data specific to said service allowing to determine the assigned time (AT) and its cost (CT) of the accounting unit,
- c. reading of a time variable (Rdate) representative of the time during which the use of said service is authorised,
- d. determination, on the basis of the time-current (TC) if it is placed during the authorisation time defined by the time variable (Rdate), and if this is the case, to authorise the service by resending the control words (CW) to the user unit (UU),
- e. if this is not the case, to order the debit of an accounting unit (CT) and to determine if the time-current (TC) is comprised in an assigned time (AT) adjacent to the time defined by the time variable (Rdate), if this is the case to determine the new value of the time variable (Rdate) in order to move the latter from an assigned time (AT), and to authorise the service resending the control words (CW) in plaintext to the user unit,
- f. if this is not the case, to load the time variable (Rdate) of an assigned time (AT) starting from the time-current (TC).
Dependencies are inferred from the claim text.