System and method of secure garbage collection on a mobile device

• US 8,973,148 B2
• Filed: 07/24/2012
• Issued: 03/03/2015
• Est. Priority Date: 03/20/2002
• Status: Expired due to Term

• Current Assignee: Cloud Software Group Switzerland GmbH
• Original Assignee: Blackberry Limited
• Inventors: Little, Herbert A., Adams, Neil P., Janhunen, Stefan E., Dahms, John F. A.
• Primary Examiner(s): Gergiso, Techane
• Application Number:
  US13/556,959
• Publication Number:
  US 20120290809A1
• Time in Patent Office: 952 Days
• Field of Search: 726/26, 707/206, 707/813
• US Class Current: 726/26
• CPC Class Codes: G06F 12/0253 Garbage collection, i.e. reclamation of unreferenced memory
• CPC Class Codes: G06F 12/0261 using reference counting
• CPC Class Codes: G06F 12/1408 by using cryptography for digital transmission H04L9/00
• CPC Class Codes: G06F 16/951 Indexing; Web crawling techniques
• CPC Class Codes: G06F 21/62 Protecting access to data via a platform, e.g. using keys or access control rules
• CPC Class Codes: G06F 2212/1044 Space efficiency improvement
• CPC Class Codes: G06F 2212/1052 Security improvement
• CPC Class Codes: G06F 2212/171 Portable consumer electronics, e.g. mobile phone
• CPC Class Codes: G06F 2212/402 Encrypted data
• CPC Class Codes: G06F 2212/702 Conservative garbage collection
• CPC Class Codes: G06F 2221/2143 Clearing memory, e.g. to prevent the data from being stolen
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 9/00 Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols

Abstract

A method and system for performing garbage collection involving sensitive information on a mobile device. Secure information is received at a mobile device over a wireless network. The sensitive information is extracted from the secure information. A software program operating on the mobile device uses an object to access the sensitive information. Secure garbage collection is performed upon the object after the object becomes unreachable.

Claims

1. A method for performing secure garbage collection involving sensitive information on a mobile device, the method comprising:

receiving secure information over a wireless network;

extracting sensitive information from the secure information;

storing the sensitive information in memory of the mobile device, wherein the sensitive information is accessible using an object;

unreferencing the object;

determining that the object has become unreachable because the object was unreferenced;

based upon the determination that the object has become unreachable, calling a wipe function to overwrite a memory of the mobile device where the unreachable object is stored; and

reclaiming the memory that the object was using.

2. The method of claim 1, wherein the mobile device is a personal digital assistant.

3. The method of claim 1, wherein the mobile device is a mobile communication device.

4. The method of claim 1, wherein the mobile device is a cellular telephone with data messaging capabilities.

5. The method of claim 1, wherein the mobile device is a wireless two-way communication device.

6. The method of claim 1, wherein the mobile device is a data messaging device.

7. The method of claim 1, wherein the mobile device is a two-way pager.

8. The method of claim 1, wherein the mobile device is a wireless Internet appliance.

9. The method of claim 1, wherein the wireless network includes means for providing the wireless network.

10. The method of claim 1, wherein the secure information is an S/MIME encrypted message.

11. The method of claim 10, wherein the sensitive information is an unencrypted version of the S/MIME message.

12. The method of claim 11, wherein the secure message was unencrypted by obtaining and applying a private key to the encrypted S/MIME message.

13. The method of claim 1, wherein the sensitive information arises from use of a Personal Information Management (PIM) application.

14. The method of claim 1, wherein overwriting the unreachable object includes overwriting the memory location where the unreachable object is stored with a sequence of bits comprising all zeros, all ones, or random data.

15. The method of claim 1, wherein the object is a user interface object configured to display the sensitive information.

16. A wireless device comprising:

a receiver configured to receive secure information over a wireless network;

a microprocessor coupled to the receiver, the microprocessor configured to extract sensitive information from the secure information;

an addressable memory configured to;

store the sensitive information, and

store an object, wherein the sensitive information is accessible using the object when the object is executed by the microprocessor; and

wherein the microprocessor is further configured to;

unreference the object,

determine that the object has become unreachable because the object was unreferenced,

based upon the determination that the object has become unreachable, call a wipe function to overwrite the addressable memory location of the unreachable object, and

reclaim the portion of the memory that the object was using.

17. The wireless device of claim 16, wherein the secure information is an S/MIME encrypted message.

18. The wireless device of claim 16, wherein overwriting the addressable memory location of the unreachable object includes overwriting the memory location with a sequence of bits comprising all zeros, all ones, or random data.

19. The wireless device of claim 16, wherein the object is a user interface object configured to display the sensitive information.