Method for validating messages
There is provided a method for secure communications. The method includes a computing device receiving a notification comprising a message, a counter value, a signature signed by a signer and based on the message and the counter value, and an indication of the signer. The device obtains a current counter value based on an identity of the signer, checks the signature and compares the counter value with the current counter value; and, if the counter comparison and the signature checking is successful, accepting the message.
1. A method of processing, at a communication device, a notification broadcast by a source server, the method comprising:
receiving, at the communication device, the notification, the notification containing a message, a message counter value, a signature, and an indication of a signer;
obtaining a previously stored current counter value associated with the signer;
comparing the message counter value with the current counter value;
in response to determining, based on the comparing, that the message counter value is not greater than the current counter value:
flagging the message to indicate a state of the message counter value relative to the current counter value; and
accepting the message.
2. The method of claim 1 , wherein the flagging comprises indicating that the message counter value is one of: less than, equal to, or greater than to the current counter value.
3. The method of claim 1 , further comprising presenting, on the communication device, a repeated warning message in response to determining that the message counter value is not greater than the current counter value.
4. The method of claim 3 , wherein presenting the repeated warning message comprises presenting, on the communication device, one or both of the message counter value and the current counter value.
5. The method of claim 3 , further comprising associating the message with a previously received message, wherein presenting the repeated warning message comprises presenting the repeated warning message with at least a portion of the previously received message.
6. The method of claim 5 , further comprising presenting metadata for both the message and the previously received message.
7. The method of claim 3 , wherein presenting the repeated warning message comprises displaying a current time and a message time associated with the repeated warning message.
8. A computing device, comprising:
a memory; and
a processor coupled to the memory, the processor being configured to:
receive a notification broadcast by a source server, the notification containing a message, a message counter value, a signature, and an indication of a signer;
obtain a previously stored current counter value associated with the signer;
compare the message counter value with the current counter value;
in response to determining, based on the comparing, that the message counter value is not greater than the current counter value:
flagging the message to indicate a state of the message counter value relative to the current counter value; and
accepting the message.
9. The computing device of claim 8 , wherein the flagging comprises indicating that the message counter value is one of: less than, equal to, or greater than to the current counter value.
10. The computing device of claim 8 , wherein the processor is further configured to present, on the computing device, a repeated warning message in response to determining that the message counter value is not greater than the current counter value.
11. The computing device of claim 10 , wherein presenting the repeated warning message comprises presenting, on the computing device, one or both of the message counter value and the current counter value.
12. The computing device of claim 10 , wherein the processor is further configured to associate the message with a previously received message, wherein presenting the repeated warning message comprises presenting the repeated warning message with at least a portion of the previously received message.
13. The computing device of claim 12 , wherein the processor is further configured to present metadata for both the message and the previously received message.
14. The computing device of claim 10 , wherein presenting the repeated warning message comprises displaying a current time and a message time associated with the repeated warning message.
15. A non-transitory machine readable medium comprising instructions that when executed on a processor of a computing device enable the computing device to:
receive a notification broadcast by a source server, the notification containing a message, a message counter value, a signature, and an indication of a signer;
obtain a previously stored current counter value associated with the signer;
compare the message counter value with the current counter value;
in response to determining, based on the comparing, that the message counter value is not greater than the current counter value:
flag the received message to indicate a state of the message counter value relative to the current counter value; and
accept the received message.