Maintaining access to services via SIM card

1. A method, comprising:

determining, by a first device, that a first subscriber identity module (SIM), previously used by the first device, is not available for use by the first device;

determining, by the first device, that a second SIM is available for use by the first device within a predetermined time period after the first SIM is determined to be not available for use by the first device; and

responsive to the determining, storing, by the first device, data that allows the first device to access, while the first SIM is unavailable for use and the second SIM is available for use, at least one service in association with a communication identifier of the first SIM.

2. The method of claim 1 , further comprising:

receiving, by the first device, a request for proof of ownership of the communication identifier of the first SIM;

sending, by the first device, a temporary certificate in response to receiving the request, wherein the temporary certificate is stored and attests to current ownership of the communication identifier of the first SIM by the first device; and

after sending the temporary certificate, accessing, by the first device, using the second SIM, the at least one service in association with the communication identifier of the first SIM.

3. The method of claim 2 , further comprising:

after sending the temporary certificate, receiving, by the first device, a message directed to the communication identifier of the first SIM via the at least one service.

4. The method of claim 1 , wherein the at least one service comprises a messaging service, wherein the messaging service is configured to allow the first device and a second device, different from the first device, to communicate by sending and receiving messages.

5. The method of claim 1 , further comprising:

confirming that: the communication identifier of the first SIM is registered for two-factor authentication of a user account, or the communication identifier of the first SIM has been associated with the user account for a threshold period of time.

6. The method of claim 2 , further comprising:

storing, by the first device, another temporary certificate that attests to current ownership of another communication identifier of the second SIM by the first device and allows the first device to access the at least one service in association with both the communication identifier of the first SIM and the other communication identifier of the second SIM.

7. The method of claim 2 , wherein the temporary certificate is associated with a predetermined expiration period after which the temporary certificate expires and is not valid.

8. The method of claim 7 , further comprising:

displaying, by the first device, an expiration notification prior to the predetermined expiration period.

9. The method of claim 7 , further comprising:

confirming, by the first device, a continued validity of the temporary certificate by polling a server using a heartbeat interval that is shorter than the predetermined expiration period.

10. The method of claim 7 , further comprising:

updating, by the first device, based on determining that the first SIM is again available for use by the first device after determining that the first SIM is not available for use by the first device, the stored temporary certificate with another temporary certificate having an extended predetermined expiration period.

11. The method of claim 2 , further comprising:

receiving, by the first device, an invalidation message corresponding to the communication identifier of the first SIM; and

invalidating, by the first device, the stored temporary certificate in response to receiving the invalidation message.

12. A first device, comprising:

a memory; and

one or more processors configured to:

determine that a first subscriber identity module (SIM), previously used by the first device, is not available for use by the first device;

determine that a second SIM is available for use by the first device within a predetermined time period after the first SIM is determined to be not available for use by the first device; and

store data that allows the first device to access, while the first SIM is unavailable for use and the second SIM is available for use, at least one service in association with a communication identifier of the first SIM.

13. The first device of claim 12 , wherein the one or more processors are further configured to:

receive a request for proof of ownership of the communication identifier of the first SIM;

send a temporary certificate in response to receiving the request, wherein the temporary certificate is stored and attests to current ownership of the communication identifier of the first SIM by the first device; and

after sending the temporary certificate, access, using the second SIM, the at least one service in association with the communication identifier of the first SIM.

14. The first device of claim 13 , wherein the one or more processors are further configured to:

after sending the temporary certificate, receive a message directed to the communication identifier of the first SIM via the at least one service.

15. The first device of claim 12 , wherein the at least one service comprises a messaging service, wherein the messaging service is configured to allow the first device and a second device, different from the first device, to communicate by sending and receiving messages.

16. The first device of claim 12 , wherein the one or more processors are further configured to confirm that:

the communication identifier of the first SIM is registered for two-factor authentication of a user account, or

the communication identifier of the first SIM is associated with the user account for a threshold period of time.

17. The first device of claim 13 , wherein the one or more processors are further configured to:

store another temporary certificate that attests to current ownership of another communication identifier of the second SIM by the first device and allows the first device to access the at least one service in association with both the communication identifier of the first SIM and the other communication identifier of the second SIM.

18. The first device of claim 13 , wherein the temporary certificate is associated with a predetermined expiration period after which the temporary certificate expires and is not valid.

19. The first device of claim 13 , wherein the one or more processors are further configured to:

receive an invalidation message corresponding to the communication identifier of the first SIM; and

invalidate the stored temporary certificate in response to receiving the invalidation message.

20. A non-transitory machine-readable medium storing instructions that, when executed by one or more processors, cause the one or more processors to:

determine that a first subscriber identity module (SIM), previously used by a first device, is not available for use by the first device;

determine that a second SIM is available for use by the first device within a predetermined time period after the first SIM is determined to be not available for use by the first device; and

store data that allows the first device to access, while the second SIM is available for use, at least one service in association with a communication identifier of the first SIM.