Monitoring usage of encrypted broadcast services

1. A method for monitoring usage of an encrypted broadcast service in a secure client module comprising a memory and being communicatively linked to a client device, the method comprising:

receiving an encrypted first entitlement control message from the client device;

decrypting the encrypted first entitlement control message;

obtaining a control word from the decrypted first entitlement control message and transmitting the control word to the client device for decrypting the encrypted broadcast service;

obtaining a first service identifier from the decrypted first entitlement control message, the first service identifier being indicative of the encrypted broadcast service;

generating, in dependence of the decrypted first entitlement control message, status data being indicative of a status of the broadcast service;

storing the first service identifier and the status data in the memory of said secure client module; and

comparing the first service identifier with a second service identifier from a second entitlement control message;

wherein if the first service identifier differs from the second service identifier and the decrypted first entitlement control message is received after the second entitlement control message, setting the status data to indicate that usage of the broadcast service has started; and

wherein if the first service identifier differs from the second service identifier and the decrypted first entitlement control message is received before the second entitlement control message, setting the status data to indicate that usage of the broadcast service has ended.

2. The method according to claim 1 , further including:

calculating an amount of time lapsed since receiving the decrypted first entitlement control message, and wherein, if the amount of time lapsed exceeds a predefined amount of time, setting the status data to indicate that usage of the broadcast service has ended.

3. The method according to claim 1 , further including:

obtaining a first monitoring instruction from the decrypted first entitlement control message and enabling or disabling the storing of the first service identifier and the status data in response to the first monitoring instruction.

4. The method according to claim 1 , further including:

receiving an encrypted entitlement management message from the client device;

decrypting the encrypted entitlement management message;

obtaining a network address of an external server from the decrypted entitlement management message; and

transmitting the first service identifier and the status data to the external server using the network address.

5. The method according to claim 4 , further including:

obtaining a second monitoring instruction from the decrypted entitlement management message; and

enabling or disabling monitoring of usage of broadcast services in response to the second monitoring instruction.

6. A secure client module for monitoring usage of an encrypted broadcast service, the secure client module being communicatively linked to a client device, the secure client module comprising:

a memory;

a receiver module configured to receive an encrypted first entitlement control message;

a decryptor configured to decrypt the encrypted first entitlement control message;

a processing module;

a first transmitter module configured to provide a control word to the client device for decrypting the encrypted broadcast service, wherein the processing module is configured to:

obtain the control word and a first service identifier from the decrypted first entitlement control message, the first service identifier being indicative of the encrypted broadcast service;

generate, in dependence of the decrypted first entitlement control message, status data being indicative of a status of the broadcast service; and

store the first service identifier and the status data in the memory, wherein the processing module is further configured to compare the first service identifier with a second service identifier from a second entitlement control message, and to set the status data to indicate that usage of the broadcast service has started if the first service identifier differs from the second service identifier and the decrypted first entitlement control message is received after the second entitlement control message, and to set the status data to indicate that usage of the broadcast service has ended if the first service identifier differs from the second service identifier and the decrypted first entitlement control message is received before the second entitlement control message.

7. The secure client module according to claim 6 , wherein the processing module is further configured to calculate an amount of time lapsed since receiving the encrypted first entitlement control message, and to set the status data to indicate that usage of the broadcast service has ended if the amount of time lapsed exceeds a predefined amount of time.

8. The secure client module according to claim 6 , wherein the processing module is further configured to obtain a first monitoring instruction from the decrypted first entitlement control message, and to enable or disable the storing of the first service identifier and the status data in response to the first monitoring instruction.

9. The secure client module according to claim 6 , further including:

a second transmitter module configured to transmit the first service identifier and the status data to an external server using a network address, and

wherein the receiver module is further configured to receive an encrypted entitlement management message, the decryptor is further configured to decrypt the encrypted entitlement management message, and the processing module is further configured to obtain the network address of the external server from the decrypted entitlement management message.

10. The secure client module according to claim 9 , wherein the processing module is further configured to obtain a second monitoring instruction from the entitlement management message and to enable or disable monitoring of usage of broadcast services in response to the second monitoring instruction.

11. The secure client module according to claim 6 , wherein the client device is a mobile phone and the secure client module is a SIM card that is detachably connected to the mobile phone.