System and method for securely storing cryptographic keys with encrypted data

• US 8,037,319 B1
• Filed: 06/30/2006
• Issued: 10/11/2011
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Operating Corporation (Gen Digital Inc.)
• Inventors: Clifford, Thomas G.
• Primary Examiner(s): Barron, Jr.; Gilberto
• Assistant Examiner(s): ZECHER, CORDELIA P K
• Application Number:
  US11/478,812
• Time in Patent Office: 1,929 Days
• Field of Search: 713/193
• US Class Current: 713/193
• CPC Class Codes: G06F 21/6218 to a system of files or objects, e.g. local or distributed file system or database
• CPC Class Codes: G06F 2221/2107 File encryption
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage

Abstract

The payload of a set of storage devices is encrypted using a payload key that is stored within the set of storage devices itself. However, the payload key is obtainable only if a user has access to n of the storage devices. A first set of keys can be distributed among a set of n storage devices, such that each key is usable to encrypt and/or decrypt a key stored on a different one of the n storage devices. The first set of keys is usable to encrypt portions of the information needed to regenerate another key (e.g., the payload key or a key used to encrypt the payload key). A different portion of the information needed to regenerate the other key is stored on each of the n storage devices. Accordingly, the other key cannot be obtained unless the user has access to all n storage devices.

Claims

1. A method comprising:

reading a first cryptographic key from a first storage device;

using the first cryptographic key to decrypt a first set of information stored on a second storage device, wherein

the second storage device is separate from the first storage device,

the first set of information stored on the second storage device comprises

at least a portion of a second cryptographic key, and

information usable to decrypt an additional portion of the second cryptographic key, and

the second cryptographic key is usable to decrypt user information stored on the first storage device.

2. The method of claim 1, wherein

a total of n storage devices must be accessed in order to obtain the cryptographic key usable to decrypt the user information stored on the first storage device, wherein n is a number larger than three.

3. The method of claim 1, further comprising:

reading an unencrypted cryptographic key from a set of information stored on a third storage device; and

using the unencrypted cryptographic key to decrypt a first set of information stored on the first storage device, prior to reading the first cryptographic key from the first storage device.

4. The method of claim 1, further comprising:

reading a first portion of a third cryptographic key from a first set of information stored on the first storage device; and

reading a second portion of the third cryptographic key from the first set of information stored on the second storage device.

5. The method of claim 4, further comprising:

using the third cryptographic key to decrypt user information stored on at least one of the first storage device and the second storage device.

6. The method of claim 4, further comprising:

using the third cryptographic key to decrypt a second set of information stored on the first storage device and a second set of information stored on the second storage device, wherein

the second set of information stored on the first storage device comprises a first portion of a fourth cryptographic key, and

the second set of information stored on the second storage device comprises a second portion of the fourth cryptographic key.

7. The method of claim 6, further comprising:

using the fourth cryptographic key to decrypt user information stored on at least one of the first storage device and the second storage device.

8. The method of claim 1, wherein the first storage device is one of:

a tape storage device, a hard drive, or an optical disc.

9. The method of claim 1, further comprising:

decrypting, based at least in part on the second cryptographic key, a second set of information, wherein

the second set of information comprises the cryptographic key usable to decrypt the user information stored on the first storage device; and

decrypting, based at least in part on the cryptographic key usable to decrypt the user information stored on the first storage device, the user information stored on the first storage device.

10. The method of claim 1, wherein:

the second cryptographic key is necessary to obtain

the cryptographic key usable to decrypt the user information stored on the first storage device.

11. The method of claim 1, wherein:

the first set of information stored on the second storage device comprises a third key; and

the third key is usable to decrypt the additional portion of the second cryptographic key.

12. A system comprising:

means for reading a first cryptographic key from a first storage device; and

means for using the first cryptographic key to decrypt a first set of information stored on a second storage device, wherein

the first set of information comprises at least a portion of a second cryptographic key, and

information usable to decrypt an additional portion of the second cryptographic key,

the second cryptographic key is usable to decrypt user information stored on the first storage device, and

the second storage device is separate from the first storage device.

13. The system of claim 12, wherein

a total of n storage devices must be accessed in order to obtain the cryptographic key usable to decrypt user information stored on the first storage device.

14. A non-transitory computer-readable storage medium comprising program instructions executable to:

read a first cryptographic key from a first storage device; and

use the first cryptographic key to decrypt a set of information stored on a second storage device, wherein

the second storage device is separate from the first storage device,

the first set of information stored on the second storage device comprises;

at least a portion of a second cryptographic key, and

information usable to decrypt an additional portion of the second cryptographic key, and

the second cryptographic key is usable to decrypt user information stored on the first storage device.

15. The non-transitory computer-readable medium of claim 14, wherein the program instructions are executable to access a total of n storage devices in order to obtain the cryptographic key usable to decrypt user information stored on the first storage device.

16. A system comprising:

a key distribution module configured to;

generate a first cryptographic key and a second cryptographic key;

subdivide the second cryptographic key into a plurality of portions;

initiate encryption of each of the portions of the second cryptographic key,

wherein

at least one portion of the second cryptographic key is encrypted using the first cryptographic key; and

store each encrypted portion of the second cryptographic key to a respective one of a plurality of storage devices, wherein

each of the storage devices stores encrypted user data,

the second cryptographic key is usable for recovery of the encrypted user data

each of the storage devices stores a different encrypted portion of the second cryptographic key,

the key distribution module is configured to;

generate a plurality of first cryptographic keys, wherein the plurality of first cryptographic keys comprises the first cryptographic key,

initiate encryption of each portion of the second cryptographic key using a respective one of the first cryptographic keys, wherein each of the first cryptographic keys is used to encrypt a different portion of the second cryptographic key, and

store each of the first cryptographic keys on a different one of the plurality of storage devices than the respective portion of the second cryptographic key.

17. The system of claim 16, further comprising:

an encryption module coupled to the key distribution module, wherein the encryption module is configured to encrypt each portion of the second cryptographic key using the respective one of the first cryptographic keys, wherein each of the first cryptographic keys is used to encrypt a different portion of the second cryptographic key.

18. A system comprising:

a processor configured to;

read a first cryptographic key from a first storage device; and

a distributed decryption module configured to;

use the first cryptographic key to decrypt a set of information stored on a second storage device, wherein

the second storage device is separate from the first storage device, and

the set of information is usable to obtain a second cryptographic key, and

the second cryptographic key is usable to obtain user information stored on the first storage device.

19. The system of claim 18, wherein

the distributed encryption module is configured to access a total of n storage devices in order to obtain the cryptographic key usable to decrypt user information stored on the first storage device.

20. A method comprising:

reading a first device key from a first storage device;

reading a first set of information stored on a second storage device, wherein

the second storage device is separate from the first storage device, and

the first set of information stored on the second storage device is stored in encrypted form on the second storage device;

using the first device key to decrypt the first set of information stored on the second storage device, wherein the first set of information stored on the second storage device comprises;

a first portion of a payload key, and

a second device key,

reading a first set of information stored on a third storage device, wherein

the third storage device is separate from the first and second storage devices, and

the first set of information stored on the third storage device is stored in encrypted form on the third storage device;

using the second device key to decrypt the first set of information stored on the third storage device, wherein the first set of information stored on the third storage device comprises

a second portion of the payload key, and

reading a payload data stored on the first storage device, wherein the payload data stored on the first storage device is stored in encrypted form on the first storage device; and

using the payload key to decrypt the payload data stored on the first storage device.

21. The method of claim 20, further comprising:

reading a first set of information stored on the first storage device; and

decrypting the first set of information stored on the first storage device, wherein the first set of information stored on the first storage device comprises

a third portion of the payload key.

22. The method of claim 20, further comprising:

reading a payload data stored on the third storage device, wherein the payload data stored on the third storage device is stored in encrypted form on the third storage device; and

using the payload key to decrypt the payload data stored on the third storage device.

23. The method of claim 22, further comprising:

reading a payload data stored on the second storage device, wherein the payload data stored on the second storage device is stored in encrypted form on the second storage device; and

using the payload key to decrypt the payload data stored on the second storage device.