Generating a traffic encryption key

1. A method for generating a traffic encryption key, the method comprising:

generating at least one traffic encryption key configured to encrypt data transmitted as part of a service, the traffic encryption key having a validity equal to a traffic encryption key validity time period;

checking whether a period for the service is longer than the traffic encryption key validity time period; and

when the period of the service is longer than the traffic encryption key validity time period,

ascertaining, by a hardware processor, a residual period which indicates by what period the service is longer than the traffic encryption key validity time period of the at least one traffic encryption key;

generating at least one residual traffic encryption key which is used for encrypting data transmitted as part of a service;

ascertaining a residual traffic encryption key validity time period which indicates for how long the residual traffic encryption key is valid, wherein ascertaining the residual traffic encryption key validity time period comprises:

checking whether the residual period is longer than a prescribed acceptable validity period; and

when the residual period is longer than the prescribed acceptable validity period, matching the residual traffic encryption key validity time period to the residual period iteratively; and

associating the residual traffic encryption key validity time period with the residual traffic encryption key.

2. The method as claimed in claim 1 , wherein each iteration of matching the residual traffic encryption key validity time period to the residual period comprises:

when the residual period is longer than the prescribed acceptable validity period, reducing a preferred traffic encryption key validity time period by a prescribed value;

checking whether the residual period is longer than the preferred traffic encryption key validity time period;

when the residual period is not longer than the reduced preferred traffic encryption key validity time period, associating the preferred traffic encryption key validity time period with the residual traffic encryption key; and

when the residual period is longer than the reduced preferred traffic encryption key validity time period, associating the reduced preferred traffic encryption key validity time period with an additional residual traffic encryption key, defining the reduced preferred traffic encryption key validity time period as the preferred traffic encryption key validity time period, reducing the residual period by the reduced preferred traffic encryption key validity time period, defining the reduced residual period as the residual period, and performing an additional iteration.

3. The method as claimed in claim 2 , wherein each iteration of matching the residual traffic encryption key validity time period to the residual period comprises:

when the residual period is longer than the prescribed acceptable validity period, reducing a preferred traffic encryption key validity time period by a value of a power to a prescribed base value.

4. The method as claimed in claim 3 , wherein each iteration of matching the residual traffic encryption key validity time period to the residual period comprises:

when the residual period is longer than the prescribed acceptable validity period, reducing a preferred traffic encryption key validity time period by a value of a power to a base value two.

5. The method as claimed in claim 1 , wherein the service is a broadcast service.

6. The method as claimed in claim 1 , wherein the service is a video broadcast service or an audio broadcast service.

7. The method as claimed in claim 1 , wherein the service is provided on the basis of an Open Mobile Alliance standard.

8. A method for transmitting data, the method comprising generating a traffic encryption key, wherein the generating the traffic encryption key comprises:

generating at least one traffic encryption key configured to encrypt data transmitted as part of a service, the traffic encryption key having a validity equal to a traffic encryption key validity time period;

checking whether a period for the service is longer than the traffic encryption key validity time period; and

when the period of the service is longer than the traffic encryption key validity time period,

ascertaining, by a hardware processor, a residual period which indicates by what period the service is longer than the traffic encryption key validity time period of the at least one traffic encryption key;

generating at least one residual traffic encryption key which is used for encrypting data transmitted as part of a service;

ascertaining a residual traffic encryption key validity time period which indicates for how long the residual traffic encryption key is valid, wherein ascertaining the residual traffic encryption key validity time period comprises:

checking whether the residual period is longer than a prescribed acceptable validity period; and

when the residual period is longer than the prescribed acceptable validity period, matching the residual traffic encryption key validity time period to the residual period iteratively; and

associating the residual traffic encryption key validity time period with the residual traffic encryption key;

encrypting data provided as part of the service using the traffic encryption key or the residual traffic encryption key; and

transmitting, by a data transmission network, the encrypted data.

9. A device for generating a traffic encryption key, the device comprising:

a first generation hardware unit configured to generate at least one traffic encryption key configured to encrypt data transmitted as part of a service, the traffic encryption key having a validity equal to a traffic encryption key validity time period;

a checking hardware unit configured to check whether a period for the service is longer than the traffic encryption key validity time period;

a first ascertainment hardware unit which is configured so that, when the period of the service is longer than the traffic encryption key validity time period, the first ascertainment hardware unit ascertains a residual period which indicates by what period the service is longer than the traffic encryption key validity time period of the at least one traffic encryption key;

a second generation hardware unit which is configured so that, when the period of the service is longer than the traffic encryption key validity time period, it generates at least one residual traffic encryption key which is used for encrypting data transmitted as part of a service;

a second ascertainment hardware unit which is configured so that, when the period of the service is longer than the traffic encryption key validity time period, it ascertains a residual traffic encryption key validity time period which indicates for how long the residual traffic encryption key is valid, wherein the second ascertainment hardware unit is further configured

to check whether the residual period is longer than a prescribed acceptable validity period; and

when the residual period is longer than the prescribed acceptable validity period, the second ascertainment hardware unit matches the residual traffic encryption key validity time period to the residual period iteratively; and

an association hardware unit which is configured so that, when the period of the service is longer than the traffic encryption key validity time period, it associates the residual traffic encryption key validity time period with the residual traffic encryption key.

10. The device as claimed in claim 9 , wherein the second generation hardware unit is further configured so that each iteration of matching the residual traffic encryption key validity time period to the residual period comprises:

when the residual period is longer than the prescribed acceptable validity period, reducing a preferred traffic encryption key validity time period by a prescribed value;

checking whether the residual period is longer than the preferred traffic encryption key validity time period;

when the residual period is not longer than the reduced preferred traffic encryption key validity time period, associating the preferred traffic encryption key validity time period with the residual traffic encryption key; and

when the residual period is longer than the reduced preferred traffic encryption key validity time period, associating the reduced preferred traffic encryption key validity time period with an additional residual traffic encryption key, defining the reduced preferred traffic encryption key validity time period as the preferred traffic encryption key validity time period, reducing the residual period by the reduced preferred traffic encryption key validity time period, defining the reduced residual period as the residual period, and performing an additional iteration.

11. The device as claimed in claim 9 , wherein the service is a broadcast service.

12. The device as claimed in claim 9 , wherein the service is a video broadcast service or an audio broadcast service.

13. The device as claimed in claim 9 , wherein the service is a service based on an Open Mobile Alliance standard.

14. A device for generating a traffic encryption key, comprising:

a first generation hardware unit configured to generate at least one traffic encryption key configured to encrypt data transmitted as part of a service, the traffic encryption key having a validity equal to a traffic encryption key validity time period;

a checking hardware unit configured to check whether a period for the service is longer than the traffic encryption key validity time period;

a direct ascertainment hardware unit is configured to ascertain, when the period of the service is longer than the traffic encryption key validity time period, a residual period which indicates by what period the service is longer than the traffic encryption key validity time period of the at least one traffic encryption key;

a second generation hardware unit is configured to generate, when the period of the service is longer than the traffic encryption key validity time period, at least one residual traffic encryption key which is used for encrypting data transmitted as part of a service;

a second ascertainment hardware unit is configured to ascertain, when the period of the service is longer than the traffic encryption key validity time period, a residual traffic encryption key validity time period which indicates for how long the residual traffic encryption key is valid, wherein the second ascertainment hardware unit is further configured

to check whether the residual period is longer than a prescribed acceptable validity period; and

when the residual period is longer than the prescribed acceptable validity period, the second ascertainment hardware unit matches the residual traffic encryption key validity time period to the residual period iteratively; and

an association hardware unit is configured to associate, when the period of the service is longer than the traffic encryption key validity time period, the residual traffic encryption key validity time period with the residual traffic encryption key.

15. A data transmission arrangement, comprising:

a data transmission device configured to transmit data as part of provision of at least one service;

a device configured to generate a traffic encryption key, comprising:

a first generation hardware unit configured to generate at least one traffic encryption key configured to encrypt data transmitted as part of a service, the traffic encryption key having a validity equal to a traffic encryption key validity time period;

a checking hardware unit configured to check whether a period for the service is longer than the traffic encryption key validity time period;

a first ascertainment hardware unit which is configured so that, when the period of the service is longer than the traffic encryption key validity time period, the first ascertainment hardware unit ascertains a residual period which indicates by what period the service is longer than the traffic encryption key validity time period of the at least one traffic encryption key;

a second generation hardware unit which is configured so that, when the period of the service is longer than the traffic encryption key validity time period, the second generation hardware unit generates at least one residual traffic encryption key which is used for encrypting data transmitted as part of a service;

a second ascertainment hardware unit which is configured so that, when the period of the service is longer than the traffic encryption key validity time period, the second ascertainment hardware unit ascertains a residual traffic encryption key validity time period which indicates for how long the residual traffic encryption key is valid, wherein the second ascertainment hardware unit is further configured

to check whether the residual period is longer than a prescribed acceptable validity period; and

when the residual period is longer than the prescribed acceptable validity period, the second ascertainment hardware unit matches the residual traffic encryption key validity time period to the residual period iteratively; and

an association hardware unit which is configured so that, when the period of the service is longer than the traffic encryption key validity time period, the association hardware unit associates the residual traffic encryption key validity time period with the residual traffic encryption key; and

an encryption device configured to encrypt the data transmitted as part of the service using the traffic encryption key or the residual traffic encryption key.