Backup system with multiple recovery keys

• US 9,904,629 B2
• Filed: 09/30/2015
• Issued: 02/27/2018
• Est. Priority Date: 05/31/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Ford, Michael D., Hauck, Jerrold V., Watson, Matthew G., Adler, Mitchell D., De Atley, Dallas B., Wilson, James
• Primary Examiner(s): Shepperd, Eric W
• Application Number:
  US14/871,498
• Publication Number:
  US 20160352518A1
• Time in Patent Office: 881 Days
• CPC Class Codes: G06F 11/1448 Management of the data involved in backup or backup restore
• CPC Class Codes: G06F 12/1408 by using cryptography for digital transmission H04L9/00
• 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 2201/80 Database-specific techniques
• CPC Class Codes: G06F 2212/1052 Security improvement
• CPC Class Codes: H04L 9/006 involving public key infrastructure [PKI] trust models network architecture or network communication protocol for supporting authentication of entities using certificates in a packet data network H04L63/0823
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
• CPC Class Codes: H04L 9/088 Usage controlling of secret information, e.g. techniques for restricting cryptographic keys to pre-authorized uses, different access levels, validity of crypto-period, different key- or password length, or different strong and weak cryptographic algorithms network architectures or network communication protocols for using time-dependent keys in a packet data network H04L63/068
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB

Abstract

Some embodiments provide, for a particular device in a set of related devices, a method for backing up data synchronized between the set of related devices. The method stores the backup data encrypted with a set of data encryption keys. The method also stores the set of data encryption keys encrypted with a master recovery key. The method also stores several copies of master recovery key data, each copy of the master recovery key data encrypted with a public key of a different one of the related devices. The backup data is only recoverable by accessing a private key of any one of the related devices.

Claims

1. For a particular device in a set of related devices, each device in the set of related devices having a public key and a private key, a method for backing up data items synchronized between the set of related devices, the method comprising:

storing the backup data items encrypted with a set of data encryption keys;

storing the set of data encryption keys encrypted with a master recovery key; and

storing a copy of master recovery key data for each device in the set of related devices, each copy of the master recovery key data encrypted using a respective public key of a respective related device, wherein after a loss of access to the synchronized data by one of the related devices, said related device restores the backup data items by (i) decrypting a respective copy of the master recovery key data using the private key of said related device and (ii) decrypting the encrypted backup data item using the decrypted master recovery key data.

2. The method of claim 1, wherein the set of data encryption keys are encrypted with a public master recovery key of a public/private master recovery key pair.

3. The method of claim 2, wherein the master recovery key data comprises one of (i) a private master recovery key of the public/private master recovery key pair and (ii) random data from which the public/private master recovery key pair is generated.

4. The method of claim 1, wherein the master recovery key is generated based on random data generated by the particular device.

5. The method of claim 1, wherein the master recovery key is not stored on any of the related devices.

6. The method of claim 1 further comprising:

encrypting the private key of the particular device, with a public escrow key of a public/private key pair generated by the particular device based on user-entered data, to create a first secure object;

encrypting the first secure object, with a public key of a set of secure servers, to create a second secure object; and

storing the second secure object with the set of secure servers.

7. The method of claim 6, wherein storing the second secure object with the set of secure servers comprises storing the second secure object with a proxy server for the set of secure servers.

8. The method of claim 6, wherein the first secure object comprises (i) the encrypted private key of the particular device and (ii) a set of verification data generated from a private escrow key of the public/private key pair generated by the particular device based on the user-entered data.

9. The method of claim 1, wherein the backup data items synchronized between the related devices comprise at least one of passwords for a plurality of web domains, cryptographic keys, and account numbers.

10. The method of claim 1, wherein the particular device receives the respective public key from each of the other related devices in order to enable the data synchronization with the other related devices.

11. The method of claim 1, wherein the encrypted backup data items, the encrypted set of data encryption keys, and the plurality of encrypted copies of the master recovery key data are stored in a cloud storage associated with a particular user account.

12. The method of claim 1, wherein the encrypted backup data items, the encrypted set of data encryption keys, and the plurality of encrypted copies of the master recovery key data are stored on a drive external to the set of related devices.

13. An electronic device that is one of a set of related devices, each device in the set of related devices having a public key and a private key, the electronic device comprising:

a set of processing units; and

a non-transitory machine readable medium storing a program which when executed by at least one of the processing units backs up data synchronized between the electronic device and the set of related devices, the program comprising sets of instructions for;

storing the backup data items encrypted with a set of data encryption keys;

storing the set of data encryption keys encrypted with a master recovery key; and

storing a copy of master recovery key data for each device in the set of related devices, each copy of the master recovery key data encrypted using a respective public key of a respective related device, wherein after a loss of access to the synchronized data by one of the related devices, said related device restores the backup data items by (i) decrypting a respective copy of the master recovery key data using the private key of said related device and (ii) decrypting the encrypted backup data item using the decrypted master recovery key data.

14. The electronic device of claim 13, wherein the set of data encryption keys are encrypted with a public master recovery key of a public/private master recovery key pair.

15. The electronic device of claim 14, wherein the master recovery key data comprises one of (i) a private master recovery key of the public/private master recovery key pair and (ii) random data from which the public/private master recovery key pair is generated.

16. The electronic device of claim 13, wherein the master recovery key is generated based on random data generated by the particular device.

17. The electronic device of claim 13, wherein the master recovery key is not stored on any of the related devices.

18. A non-transitory machine readable medium storing a program which when executed by at least one processing unit of a particular device in a set of related devices backs up data synchronized between the set of related devices, each device in the set of related devices having a public key and a private key, the program comprising sets of instructions for:

storing the backup data items encrypted with a set of data encryption keys;

storing the set of data encryption keys encrypted with a master recovery key; and

storing a copy of the master recovery key data for each device in the set of related devices, each copy of the master recovery key data encrypted using a respective public key of a respective related device, wherein after a loss of access to the synchronized data by one of the related devices, said related device restores the backup data items by (i) decrypting a respective copy of the master recovery key data using the private key of said related device and (ii) decrypting the encrypted backup data item using the decrypted master recovery key data.

19. The non-transitory machine readable medium of claim 18, wherein the program further comprises sets of instructions for:

encrypting the private key of the particular device, with a public escrow key of a public/private key pair generated by the particular device based on user-entered data, to create a first secure object;

encrypting the first secure object, with a public key of a set of secure servers, to create a second secure object; and

storing the second secure object with the set of secure servers.

20. The non-transitory machine readable medium of claim 19, wherein the set of instructions for storing the second secure object with the set of secure servers comprises a set of instructions for storing the second secure object with a proxy server for the set of secure servers.

21. The non-transitory machine readable medium of claim 19, wherein the first secure object comprises (i) the encrypted private key of the particular device and (ii) a set of verification data generated from a private escrow key of the public/private key pair generated by the particular device based on the user-entered data.

22. The non-transitory machine readable medium of claim 18, wherein the particular device receives the respective public key from each of the other related devices.