System and method of filtering unsolicited messages

1. A method in a subscriber device for filtering unsolicited notification messages, the method comprising:

generating, at a subscriber device, a subscriber secure correlation identifier (SCID) associated with a subscription to a subscribed event source, wherein the subscriber SCID comprises a randomized correlation identifier and a secure tag, wherein the secure tag is generated using the randomized correlation identifier and a device encryption key associated with the subscriber device; and

providing the subscriber SCID to the subscribed event source in a subscription message;

receiving, at the subscriber device, a notification message upon occurrence of an event, the notification message having an event-source SCID comprising a first portion and a second portion;

verifying, in the subscriber device, that the notification message is from the subscribed event source if the second portion of the event-source SCID is equal to a secure hash of the first portion of the event-source SCID, wherein the secure hash is generated using the first portion and the device encryption key; and

accepting the notification message if the notification message is verified as being from the subscribed event source.

2. The method as claimed in claim 1 , wherein the verifying comprises:

retrieving the event-source SCID from the notification message;

dividing the event-source SCID into the first portion and the second portion;

determining that the notification message is from the subscribed event source if the second portion is equal to a secure hash of the first portion; and

determining that the notification message is not from the subscribed event source if the second portion is not equal to a secure hash of the first portion.

3. The method as claimed in claim 2 , wherein the retrieving the event-source SCID comprises obtaining the event-source SCID from a uniform resource locator.

4. The method as claimed in claim 2 , wherein the first portion and the second portion are divided from the event-source SCID using a predetermined function.

5. The method as claimed in claim 2 , wherein dividing the event-source SCID comprises parsing a predetermined length of the event-source SCID to obtain the first portion, the remainder being the second portion.

6. The method as claimed in claim 2 , wherein dividing the event-source SCID comprises parsing a predetermined length of the event-source SCID to obtain the second portion, the remainder being the first portion.

7. The method as claimed in claim 1 , wherein generating the subscriber SCID comprises:

generating a correlation identifier (CID) for the subscription;

generating a sequence of random bits (R);

concatenating the correlation identifier with the sequence of bits resulting in a CIDR;

generating a sequence of secure tag bits (H) by performing a secure tag function on the CIDR and the device encryption key; and

concatenating the CIDR with the H.

8. The method claimed in claim 7 , wherein the secure tag function is a message authentication code function.

9. The method claimed in claim 7 , wherein the secure tag function is a digital signature function.

10. The method as claimed in claim 1 , further comprising:

listening for the notification message from the event source; and

forwarding an accepted notification message to a messaging subsystem of the subscriber device.

11. The method as claimed in claim 1 , further comprising:

monitoring a notification rate of notification messages received per minute per event-source SCID per Internet protocol (IP) address; and

blocking notification messages from IP addresses if the notification rate exceeds a predetermined threshold for a given event-source SCID and IP address.

12. The method as claimed in claim 1 , further comprising:

checking expiry information of the subscriber SCID; and

rejecting notification messages having an expired subscriber SCID.

13. The method of claim 1 , further comprising:

rejecting the notification message if the notification message is not verified as being from the subscribed event source.

14. A secure correlation identifier (SCID) authentication system in a subscriber device for filtering unsolicited notification messages, the SCID authentication system comprising:

a message listener configured to receive a notification message upon occurrence of an event, the notification message having an event-source SCID comprising a first portion and a second portion; and

a SCID authenticator configured to:

generate a subscriber SCID associated with a subscription to a subscribed event source, wherein the subscriber SCID comprises a randomized correlation identifier and a secure tag, wherein the secure tag is generated using the randomized correlation identifier and a device encryption key associated with the subscriber device; and

provide the subscriber SCID to the subscribed event source in a subscription message;

upon the message listener receiving the notification message, verify that the notification message is from the subscribed event source if the second portion of the event-source SCID is equal to a secure hash of the first portion of the event-source SCID, wherein the secure hash of the first portion is generated using the first portion and the device encryption key; and

accept the notification message if the notification message is verified as being from the subscribed event source.

15. The SCID authentication system as claimed in claim 14 , further comprising a message parser for obtaining the event-source SCID from the notification message.

16. The SCID authentication system as claimed in claim 14 , further comprising a notification counter for monitoring a notification rate of notification messages received per minute per event-source SCID per Internet protocol (IP) address.

17. A computer program product for filtering unsolicited messages, the computer program product comprising a non-transitory computer readable medium embodying program code means for implementing a method in a subscriber device for filtering unsolicited notification messages, the method comprising:

generating, at a subscriber device, a subscriber secure correlation identifier (SCID) associated with a subscription to a subscribed event source, wherein the subscriber SCID comprises a randomized correlation identifier and a secure tag, wherein the secure tag is generated using the randomized correlation identifier and a device encryption key associated with the subscriber device; and

providing the subscriber SCID to the subscribed event source in a subscription message;

receiving a notification message upon an occurrence of an event, the notification message having an event-source SCID comprising a first portion and a second portion;

verifying that the notification message is from the subscribed event source if the second portion of the event-source SCID is equal to a secure hash of the first portion of the event-source SCID, wherein the secure hash is generated using the first portion and the device encryption key;

accepting the notification message if the notification message is verified as being from the subscribed event source.