Handling identifier validation

1. A method, performed by a wireless device, for calculating a subscription concealed identifier (SUCI), the method comprising the wireless device:

receiving a message indicating a criterion associated with a size of a SUCI;

calculating the SUCI based on an encryption scheme;

determining whether the calculated SUCI satisfies the criterion associated with the size of the SUCI; and

using the calculated SUCI only when it is determined that the calculated SUCI satisfies the criterion associated with the size of the SUCI.

2. The method of claim 1 , wherein the using the calculated SUCI comprises not sending the calculated SUCI when it is determined that the calculated SUCI does not satisfy the criterion associated with the size of the SUCI.

3. The method of claim 1 , wherein the receiving the message indicating the criterion associated with the size of a SUCI comprises receiving the message in a broadcast message.

4. The method of claim 1 , wherein the receiving the message indicating the criterion associated with the size of a SUCI comprises receiving the message indicating the criterion associated with the size of a SUCI in a protocol message sent specifically to the wireless device.

5. The method of claim 1 , wherein the criterion associated with the size of the SUCI comprises a maximum size.

6. The method of claim 1 , wherein the criterion associated with the size of the SUCI comprises a minimum size.

7. The method of claim 1 , wherein the criterion associated with the size of the SUCI comprises a size range.

8. A method, performed by a network function, to identify an invalid subscription concealed identifier (SUCI), the method comprising the network function:

receiving a message containing a SUCI;

determining a size of the SUCI contained in the received message;

determining an expected size of the SUCI in the received message;

determining whether the size of the SUCI contained in the received message satisfies a criterion associated with the expected size;

determining that the SUCI in the received message is invalid when the size of the SUCI contained in the received message does not satisfy the criterion associated with the expected size; and

rejecting the SUCI in the received message when the SUCI in the received message is determined to be invalid.

9. The method of claim 8 , wherein the determining the expected size of the SUCI comprises determining the expected size of the SUCI in the received message based on an encryption scheme used for calculating the SUCI.

10. The method of claim 9 , further comprising receiving a message containing an encryption scheme identifier indicating the encryption scheme used for calculating the SUCI.

11. The method of claim 10 , wherein the encryption scheme used for calculating the SUCI is a standardized encryption scheme.

12. The method of claim 10 , wherein the encryption scheme used for calculating the SUCI is a proprietary encryption scheme.

13. The method of claim 8 , wherein the expected size of the SUCI in the received message applies to all SUCIs in the network.

14. The method of claim 8 , wherein the expected size of the SUCI in the received message applies to all SUCIs in a local area of the network.

15. The method of claim 8 , wherein the determining the expected size of the SUCI comprises determining the expected size of the SUCI in the received message based on at least one other factor.

16. The method of claim 15 , wherein the at least one other factor comprises: time, location, network load, network type, operator information, or roaming partner information.

17. The method of claim 8 , wherein the criterion associated with the expected size comprises a maximum size that is greater than the expected size.

18. The method of claim 8 , wherein the criterion associated with the expected size comprises a minimum size that is smaller than the expected size.

19. The method of claim 8 , wherein the criterion associated with the expected size comprises a size range that encompasses the expected size.

20. A wireless device configured to calculate a subscription concealed identifier (SUCI), the wireless device comprising:

processing circuitry;

memory containing instructions executable by the processing circuitry whereby the wireless device is operative to:

receive a message indicating a criterion associated with a size of a SUCI;

calculate the SUCI based on an encryption scheme;

determine whether the calculated SUCI satisfies the criterion associated with the size of the SUCI; and

use the calculated SUCI only when it is determined that the calculated SUCI satisfies the criterion associated with the size of the SUCI.

21. A network node configured to identify an invalid subscription concealed identifier (SUCI), the network node comprising:

processing circuitry;

memory containing instructions executable by the processing circuitry whereby the network node is operative to:

receive a message containing a SUCI;

determine a size of the SUCI contained in the received message;

determine an expected size of the SUCI in the received message;

determine whether the size of the SUCI contained in the received message satisfies a criterion associated with the expected size;

determine that the SUCI in the received message is invalid when the size of the SUCI contained in the received message does not satisfy the criterion associated with the expected size; and

reject the SUCI in the received message when the SUCI in the received message is determined to be invalid.