Encryption key destruction for secure data erasure
View Patent ↗Techniques for encryption key destruction for secure data erasure via an external interface or physical key removal are described. Electrical destruction of key material retained in a memory of a storage device renders the device securely erased, even when the device is otherwise inoperable. The memory (e.g. non-volatile, such as flash) stores key material for encrypting/decrypting storage data for the device. An eraser provides power and commands to the memory, even when all or any portion of the device is inoperable. The commands (e.g. erase or write) enable zeroizing or destroying the key material, rendering data encrypted with the destroyed key material inaccessible, and therefore securely erased. Alternatively, the memory is a removable component (e.g. an external security device or smartcard) coupled to the device during storage operation. Removing and physically destroying the memory renders the device securely erased. The device and/or the memory are sealed to enable tamper detection.
1. A storage device comprising:
an external interface enabled to couple to a host via a storage interface protocol;
a data storage medium;
a Non-Volatile Memory (NVM) containing a cryptographic key, the NVM coupled to one or more elements of the storage device such that the NVM is a part of a removable component physically separate from the data storage medium, and the removable component is sealed with a seal while coupled to the elements to enable tamper detection;
a logic circuit enabled to encrypt/decrypt data stored into/read from the data storage medium using the cryptographic key; and
wherein any of the data encrypted using the cryptographic key and kept stored in the data storage medium is rendered inaccessible by erasure and/or destruction of the NVM.
2. The storage device of claim 1 , wherein removal of the removable component results in the seal being broken.
3. The storage device of claim 1 , wherein the removable component is compatible with a form factor of at least one of
a Smartcard,
a USB storage component,
a CF storage component,
an MMC storage component,
an SD storage component,
a Memory Stick storage component, and
an xD-picture card storage component.
4. The storage device of claim 1 , wherein the data storage medium comprises non-volatile memory technology.
5. The storage device of claim 1 , wherein the data storage medium comprises rotating disk technology.
6. A system comprising:
a storage device enabled to encrypt and decrypt data according to a cryptographic key stored at least in part in an included Non-Volatile Memory (NVM), the storage device having an external interface to the NVM;
an eraser device, physically separate from the storage device, and enabled to couple to the external interface;
wherein the eraser device, when coupled to the external interface, is further enabled to destroy at least the part of the cryptographic key, the destroying comprising providing operating power to the NVM; and
wherein any of the data encrypted using the cryptographic key and kept stored in the storage device is rendered inaccessible by the destroying.
7. The system of claim 6 , wherein the destroying comprises at least partial overwriting of the NVM with a non-secret pattern.
8. The system of claim 6 , wherein the destroying comprises at least partial zeroizing of the NVM.
9. The system of claim 6 , wherein the destroying comprises at least partial erasure of the NVM.
10. The system of claim 6 , wherein the eraser device is further enabled to perform the destroying when one or more components of the storage device are inoperable.
11. The system of claim 6 , further comprising a data storage memory storing at least a portion of encrypted data of the storage device.
12. The system of claim 11 , wherein the NVM is a first NVM, the data storage memory is a second NVM, and the cryptographic key is determined at least in part in accordance with one or more programming counts associated with one or more physical blocks of the second NVM.
13. The system of claim 11 , wherein the data storage memory comprises a rotating disk.
14. The system of claim 6 , wherein the storage device is sealed in a mechanical enclosure having a seal that is broken to couple the eraser device to the storage device.
15. The system of claim 6 , wherein the cryptographic key is determined at least in part in accordance with one or more addresses associated with all or any portion of the data.
16. A method comprising:
coupling an eraser device to an external interface of a storage device, the eraser device being, before the coupling, physically separate from the storage device, the external interface being to a Non-Volatile Memory (NVM) of the storage device;
destroying, via the coupled eraser device, cryptographic material stored in the NVM, the destroying comprising providing operating power to the NVM;
wherein the storage device is enabled to encrypt and decrypt data at least in part according to the cryptographic material; and
wherein any of the data encrypted using the cryptographic material and kept stored in the storage device is rendered inaccessible by the destroying.
17. The method of claim 16 , wherein the destroying comprises at least partial overwriting of the NVM with a non-secret pattern.
18. The method of claim 16 , wherein the destroying comprises at least partial zeroizing of the NVM.
19. The method of claim 16 , wherein the destroying comprises at least partial erasure of the NVM.
20. The method of claim 16 , further comprising repairing the storage device after the destroying.
21. The method of claim 16 , wherein the storage device is sealed in a mechanical enclosure having a seal, and performing the coupling comprises breaking the seal.
22. The method of claim 16 , further comprising determining the cryptographic material at least in part in accordance with one or more addresses associated with all or any portion of the data.
23. The method of claim 16 , wherein a data storage memory is used to store at least a portion of encrypted data of the storage device.
24. The method of claim 23 , wherein the NVM is a first NVM, the data storage memory is a second NVM, and the cryptographic material is determined at least in part in accordance with one or more programming counts associated with one or more physical blocks of the second NVM.
25. The method of claim 23 , wherein the data storage memory comprises a rotating disk.
26. A system comprising:
an eraser device enabled to couple to an external interface of a storage device, the eraser device being physically separate from the storage device, the external interface being to a Non-Volatile Memory (NVM) of the storage device;
means for destroying, when the eraser device is coupled to the storage device via the external interface, cryptographic material stored in the NVM, the means for destroying being comprised in the erasure device, and the means for destroying comprising means for providing operating power to the external interface and the NVM;
wherein the storage device is enabled to encrypt and decrypt data at least in part according to the cryptographic material; and
wherein any of the data encrypted using the cryptographic material and kept stored in the storage device is rendered inaccessible by the destroying.
27. The system of claim 26 , wherein the means for destroying implements any one or more of
at least partial overwriting of the NVM with a non-secret pattern,
at least partial zeroizing of the NVM, and
at least partial erasure of the NVM.