Local keying for self-encrypting drives (SED)
A method and system self encrypts a disk storage device. Given a plurality of data storage devices, the system establishes an encryption key for the plurality of data storage devices. The system locally stores the encryption key in a piecewise manner throughout the plurality of data storage devices such that the encryption key is rendered undeterminable with less than a threshold subset of the plurality of data storage devices. This results in the plurality of data storage devices being self encrypting. Upon an increase or decrease in the plurality, the system resplits the encryption key and locally stores the resulting pieces throughout the changed (increased/decreased) plurality of data storage devices. This renders the encryption key undeterminable with less than a new or revised threshold each time the plurality is changed.
1. A method of self encrypting a disk storage device comprising:
providing a plurality of data storage devices;
establishing an access key for the plurality of data storage devices;
determining a media encryption key using a random number generator;
encrypting data stored on the plurality of data storage devices using the media encryption key; encrypting the media encryption key using the access key;
locally storing shares of the access key in a first piecewise manner throughout the plurality of data storage devices such that the access key is rendered undeterminable with less than a threshold subset of the locally stored shares stored on the plurality of data storage devices, resulting in the plurality of data storage devices being self encrypted;
generating a set of backup shares of the access key in a second piecewise manner being stored on a plurality of backup data storage devices, the set of backup shares of the access key remaining operable after removal or addition of any of the plurality of data storage devices and further remaining operable after change to the shares of the access key;
responsive to changing the plurality of storage devices:
re-computing a new piecewise manner to store the access key throughout the plurality of data storage devices, by splitting the access key into a set of shares that are different than the locally stored shares before the change to the plurality of storage devices; and
storing different shares of the set of shares on different ones of the changed plurality of data storage devices,
wherein the re-computing the new piecewise local storing of the access key renders the access key undeterminable with less than a new threshold, the new threshold being a subset of the changed plurality of data storage devices,
wherein the change to the plurality of data storage devices is any of removal of one or more data storage devices from the plurality and addition of one or more data storage devices to the plurality, resulting in increase or decrease of a number of data storage devices of the plurality; and
wherein the set of backup shares have shares with a different threshold subset from the threshold subset of the locally stored shares.
2. A method of claim 1 wherein the step of locally storing the access key in a piecewise manner applies a secret sharing process.
3. A method of claim 2 wherein the secret sharing process is Shamir's secret sharing.
4. A method of claim 2 wherein the secret sharing process includes:
splitting the access key into N pieces (shares);
storing different ones of the pieces on N different ones of the plurality of data storage devices, such that the threshold subset of the plurality is (N+1)/2 of the data storage devices.
5. A method of claim 1 wherein the plurality of data storage devices is a RAID (Redundant Array of Independent Disks) configuration.
6. A method of claim 1 wherein the encrypted data stored on the plurality of data storage devices is in a band of a data storage device.
7. A method of claim 1 wherein the access key is a user-generated password.
8. The method of claim 1 , further comprising:
responsive to one of the set of backup shares being compromised, generating a new set of backup shares.
9. A self encrypting data storage system comprising:
a plurality of data storage devices; and
an encryption engine configured to:
establish an access key for the plurality of data storage devices,
determine a media encryption key using a random number generator,
encrypt data stored on the plurality of data storage devices using the media encryption key,
encrypt the media encryption key using the access key,
locally store shares of the access key in a first piece wise manner throughout the plurality of data storage devices such that the access key is rendered undeterminable with less than a threshold subset of the locally stored shares stored on the plurality of data storage devices, resulting in the plurality of data storage devices being self encrypted;
generate a set of backup shares of the access key in a second piecewise manner being stored on a plurality of backup data storage devices, the set of backup shares of the access key remaining operable after removal or addition of any of the plurality of data storage devices and further remaining operable after change to the shares of the access key;
upon a change to the plurality of data storage devices:
re-compute a new piecewise manner to store the access key throughout the plurality of data storage devices, by splitting the access key into a set of shares that are different from the locally stored shares before the change to the plurality of storage devices, and
store different shares of the set of pieces on different ones of the changed plurality of data storage devices,
wherein the re-computing the new piecewise manner of the access key renders the access key undeterminable with less than a new threshold, the new threshold being a subset of the changed plurality of data storage devices,
wherein the change to the plurality of data storage devices is any of removal of one or more data storage devices from the plurality and addition of one or more data storage devices to the plurality, resulting in increase or decrease of the plurality; and
wherein the set of backup shares have shares with a different threshold subset from the threshold subset of the locally stored shares.
10. The self encrypting data storage system of claim 9 wherein the encryption engine locally stores the access key in a piece wise manner by applying a secret sharing process.
11. The system of claim 10 wherein the secret sharing process is Shamir's secret sharing.
12. The system of claim 10 wherein the encryption engine applies the secret sharing process by:
splitting the access key into N pieces (shares);
storing different ones of the pieces on N different ones of the plurality of data storage devices, such that the threshold subset of the plurality is (N+1)/2 of the data storage devices.
13. The system of claim 9 wherein the plurality of data storage devices is a RAID (Redundant Array of Independent Disks) configuration.
14. The system of claim 9 wherein the encrypted data stored on the plurality of data storage devices is in a band of a data storage device.
15. The system of claim 9 wherein the access key is a user-generated password.
16. A data handling system comprising:
a plurality of data storage devices, the data storage devices being self-encrypting; and
an encryption engine configured to:
establish an access key for the plurality of data storage devices,
determine a media encryption key using a random number generator,
encrypt data stored on the plurality of data storage devices using the media encryption key,
encrypt the media encryption key using the access key,
locally store shares of the access key in a piece wise manner throughout the plurality of data storage devices such that the access key is rendered undeterminable with less than a threshold subset of the locally stored shares stored on the plurality of data storage devices, resulting in the plurality of data storage devices being self encrypted,
generate a set of backup shares of the access key in a second piecewise manner being stored on a plurality of backup data storage devices, the set of backup shares of the access key remaining operable after removal or addition of any of the plurality of data storage devices and further remaining operable after change to the shares of the access key; and
responsive to a change to the plurality of data storage devices:
(i) re-computing a new piecewise manner to store the access key throughout the changed plurality of data storage devices, by splitting the access key into a set of shares that are different than the locally stored shares used before the change to the plurality of storage devices, and
(ii) store different pieces of the set of pieces throughout the changed plurality of data storage devices,
wherein the re-computing the new piecewise manner of the access key renders the encryption key undeterminable with less than a new threshold, the new threshold being a subset of the changed plurality of data storage devices;
wherein the change to the plurality of data storage devices is any of removal of one or more data storage devices from the plurality and addition of one or more data storage devices to the plurality, resulting in increase or decrease of the plurality; and
wherein the set of backup shares have shares with a different threshold subset from the threshold subset of the locally stored shares.
17. The system of claim 16 wherein the encryption engine locally stores the access key in a piece wise manner by applying a secret sharing process that includes:
splitting the access key into N pieces (shares);
storing different ones of the N pieces on N different ones of the plurality of data storage devices, such that the threshold subset of the plurality is (N+1)/2 of the data storage devices.
18. The system of claim 16 wherein the encrypted data stored on the plurality of data storage devices is in a band of a data storage device.
19. The system of claim 16 wherein the access key is a user-generated password.