Dynamically resolving recipients to retrieve public keys during send/receive

• US 7,716,479 B2
• Filed: 06/03/2005
• Issued: 05/11/2010
• Est. Priority Date: 06/03/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Gupta, Anoop, Kroman, Paul K., Hall, Gary W., Vargas, Garrett R., Nalliah, Selvaraj, Counts, Eian D.
• Primary Examiner(s): Zand; Kambiz
• Assistant Examiner(s): BAYOU, YONAS A
• Application Number:
  US11/144,896
• Publication Number:
  US 20060288211A1
• Time in Patent Office: 1,803 Days
• Field of Search: 713/153
• US Class Current: 713/170
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/06 for supporting key management in a packet data network cryptographic mechanisms or cryptographic arrangements for key management H04L9/08
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 9/12 Transmitting and receiving encryption devices synchronised or initially set up in a particular manner
• CPC Class Codes: H04L 9/30 Public key, i.e. encryption algorithm being computationally infeasible to invert or user's encryption keys not requiring secrecy

Abstract

Systems and methods are disclosed that facilitate identifying messages generated on a mobile device while the device is offline as requiring encryption, storing the messages in a message outbox with a flag indicating that encryption is required, and identifying recipients of the flagged messages to generate a recipient list. The recipient list can be piggybacked on a server synchronization request when the mobile device enters a period of online activity, and a server can return public keys associated with identified recipients to permit an encryption component, such as a secure/multipurpose Internet mail extension protocol (S/MIME) encryption component, in the mobile device to encrypt the messages.

Claims

1. A method of dynamically retrieving public keys for message encryption during a send/receive process in a mobile device, comprising:

identifying a message to be encrypted and storing the message in a message outbox while the mobile device is offline; and

in response to determining that the mobile device is entering a period of online activity;

assessing messages in the outbox and identifying an intended recipient for the message identified to be encrypted, and

generating a synchronization request for synchronizing communication between the mobile device and a server, the synchronization request comprising a request for a public key for the identified intended recipient.

2. The method of claim 1, wherein identifying the message to be encrypted further comprises associating the message with a unique property during storage that identifies the message as requiring a public key.

3. The method of claim 1, wherein identifying an intended recipient comprises identifying a recipient associated with the message utilizing a recipient identification API.

4. The method of claim 3, wherein generating a synchronization request comprises adding the recipient identified by the recipient identification API to a server synchronization request and transmitting the server synchronization request to an exchange server.

5. The method of claim 4, wherein generating a synchronization request further comprises resolving the identified recipient against the server and retrieving a public key for the identified recipient.

6. The method of claim 5, further comprising employing the public key to encrypt the message and transmitting the encrypted message to the recipient.

7. The method of claim 6, further comprising employing an S/MIME encryption technique to encrypt the message upon receipt of the public key.

8. The method of claim 1, performed on a plurality of messages having a plurality of intended recipients.

9. The method of claim 1, further comprising generating an error message when a public key cannot be determined for a recipient associated with the identified message to be encrypted.

10. The method of claim 9, further comprising storing the error message in an inbox data store for the mobile device and storing the original message to be encrypted in a draft data store.

11. A computer-readable medium having stored thereon computer executable instructions for carrying out the method of claim 1.

12. A computer-implemented system that facilitates retrieving public keys associated with intended message recipients, comprising:

a data store that stores messages to be encrypted, which are generated during periods of offline activity for a client device; and

a resolution component, the resolution component adapted to;

in response to determining that the mobile device is entering a period of on-line activity;

assess messages in the data store and identify an intended recipient for at least one message, and

generate a synchronization request for synchronizing communication between the mobile device and a server, the synchronization request comprising a request for a public key for the identified intended recipient.

13. The system of claim 12, wherein the resolution component comprises a synchronization component that generates a synchronization request to synchronize the client device to the message exchange server.

14. The system of claim 13, wherein the resolution component comprises a recipient identification component that identifies the intended recipient for the at least one message and adds a recipient name to the server synchronization request.

15. The system of claim 14, wherein the resolution component issues a command to the server to resolve the recipient name against the server, and retrieve a public key for the recipient.

16. The system of claim 15, further comprising an encryption component that encrypts a message flagged for encryption utilizing the public key retrieved by the resolution component at synchronization time.

17. The system of claim 16, the encryption component is an S/MIME encryption component.

18. A system that facilitates retrieving public keys for recipients of encrypted messages over a communication network, comprising:

means for identifying messages to be encrypted for transmission from an offline mobile device;

means for storing identified messages;

means for;

in response to determining that the mobile device is entering a period of online activity;

assessing stored messages and identifying a recipient for each identified message in; and

generating a synchronization request for synchronizing communication between the mobile device and a server, the synchronization request comprising a request for a public key for each identified recipient; and

means for inferring a public key when a public key is not returned in response to the synchronization request.