Power failure tolerant cryptographic erase
First Claim
1. A method of cryptographically erasing data in a storage device, at a controller of the storage device, the storage device having a first encryption key established as a current encryption key prior to performance of the method, the method comprising:
- updating a durably stored progress indicator to indicate a first stage;
performing a set of first stage operations, including;
obtaining a second encryption key;
in accordance with a determination that a power fail condition did not occur while the progress indicator indicates the first stage;
updating the progress indicator to indicate a second stage;
performing a set of second stage operations, including;
storing, in a first set of memory blocks on the storage device, a first set of metadata corresponding to the first set of memory blocks, encrypted using the second encryption key; and
storing, in the first set of memory blocks, a second set of metadata corresponding to a second set of memory blocks on the storage device, encrypted using the second encryption key;
wherein the second set of memory blocks does not comprise any memory block in the first set of memory blocks; and
,in accordance with a determination that a power fail condition did not occur while the progress-counter indicates the second stage;
updating the progress indicator to indicate a third stage;
performing a set of third stage operations, including storing, in the second set of memory blocks, the second set of metadata encrypted using the second encryption key; and
subsequent to storing, in the second set of memory blocks, the second set of metadata encrypted using the second encryption key, setting the second encryption key as the current encryption key for the plurality of memory blocks.
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Accused Products
Abstract
The various implementations described herein include systems, methods and/or devices used to enable power failure tolerant cryptographic erasure in a storage device having a first encryption key established as a current encryption key. The method includes performing a set of first stage operations including selecting first and second sets of memory blocks and obtaining a second encryption key. The method includes performing a set of second stage operations including storing, in the first set of memory blocks, first and second sets of metadata, encrypted using the second encryption key. The method includes performing a set of third stage operations, including storing, in the second set of memory blocks, the second set of metadata encrypted using the second encryption key. The method includes setting the second encryption key as the current encryption key for the plurality of memory blocks.
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Citations
30 Claims
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1. A method of cryptographically erasing data in a storage device, at a controller of the storage device, the storage device having a first encryption key established as a current encryption key prior to performance of the method, the method comprising:
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updating a durably stored progress indicator to indicate a first stage; performing a set of first stage operations, including; obtaining a second encryption key; in accordance with a determination that a power fail condition did not occur while the progress indicator indicates the first stage; updating the progress indicator to indicate a second stage; performing a set of second stage operations, including; storing, in a first set of memory blocks on the storage device, a first set of metadata corresponding to the first set of memory blocks, encrypted using the second encryption key; and storing, in the first set of memory blocks, a second set of metadata corresponding to a second set of memory blocks on the storage device, encrypted using the second encryption key;
wherein the second set of memory blocks does not comprise any memory block in the first set of memory blocks; and
,in accordance with a determination that a power fail condition did not occur while the progress-counter indicates the second stage; updating the progress indicator to indicate a third stage; performing a set of third stage operations, including storing, in the second set of memory blocks, the second set of metadata encrypted using the second encryption key; and subsequent to storing, in the second set of memory blocks, the second set of metadata encrypted using the second encryption key, setting the second encryption key as the current encryption key for the plurality of memory blocks. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of cryptographically erasing data in a storage device having a first set of memory blocks and a second set of memory blocks, wherein the second set of memory blocks does not comprise any memory block in the first set of memory blocks, the first set of memory blocks storing a first set of metadata and the second set of memory blocks storing a second set of metadata, the storage device further having a first encryption key established as a current encryption key, to encrypt metadata and data, if any, in at least the first and second sets of memory blocks, prior to performance of the method, the method comprising:
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performing a power-failure tolerant cryptographic erase operation, including; obtaining and storing a second encryption key; storing, in the first set of memory blocks, the second set of metadata encrypted with the second encryption key; subsequent to storing, in the first set of memory blocks, the second set of metadata encrypted with the second encryption key, storing the second set of metadata encrypted with the second encryption key at corresponding locations in the second set of memory blocks; storing the first set of metadata encrypted with the second encryption key in the first set of memory blocks; and establishing the second encryption key as the current encryption key to encrypt metadata and data, if any, in at least the first and second sets of memory blocks, wherein performing the cryptographic erase operation further comprises; storing in non-volatile memory a progress indicator that indicates a stage of the cryptographic erase operation, and updating the progress indicator upon completion of each stage of a predefined set of stages of the cryptographic erase operation; determining whether a power failure has occurred while performing the cryptographic erase operation; and
,in accordance with a determination that a power failure has occurred while performing the cryptographic erase operation, resuming performance of the cryptographic erase operation at a stage corresponding to a value of the progress indicator. - View Dependent Claims (21, 22)
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12. A storage device, comprising:
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an interface for coupling the storage device to a host system; and a controller having one or more processors, the controller configured to; update a durably stored progress indicator to indicate a first stage; perform a set of first stage operations, including; obtain a second encryption key; in accordance with a determination that a power fail condition did not occur while the progress indicator indicates the first stage; update the progress indicator to indicate a second stage; perform a set of second stage operations, including; store, in a first set of memory blocks on the storage device, a first set of metadata corresponding to the first set of memory blocks, encrypted using the second encryption key; and store, in the first set of memory blocks, a second set of metadata corresponding to a second set of memory blocks on the storage device, encrypted using the second encryption key, wherein the second set of memory blocks does not comprise any memory block in the first set of memory blocks; and
,in accordance with a determination that a power fail condition did not occur while the progress-counter indicates the second stage; update the progress indicator to indicate a third stage; perform a set of third stage operations, including storing, in the second set of memory blocks, the second set of metadata encrypted using the second encryption key; and
,subsequent to storing, in the second set of memory blocks, the second set of metadata encrypted using the second encryption key, set the second encryption key as the current encryption key for the plurality of memory blocks. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A non-transitory computer readable storage medium, storing one or more programs for execution by one or more processors of a storage device, the one or more programs including instructions for:
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updating a durably stored progress indicator to indicate a first stage; performing a set of first stage operations, including; obtaining a second encryption key; in accordance with a determination that a power fail condition did not occur while the progress indicator indicates the first stage; updating the progress indicator to indicate a second stage; performing a set of second stage operations, including; storing, in a first set of memory blocks on the storage device, a first set of metadata corresponding to the first set of memory blocks, encrypted using the second encryption key; and storing, in the first set of memory blocks, a second set of metadata corresponding to a second set of memory blocks on the storage device, encrypted using the second encryption key, wherein the second set of memory blocks does not comprise any memory block in the first set of memory blocks; and
,in accordance with a determination that a power fail condition did not occur while the progress-counter indicates the second stage; updating the progress indicator to indicate a third stage; performing a set of third stage operations, including storing, in the second set of memory blocks, the second set of metadata encrypted using the second encryption key; and subsequent to storing, in the second set of memory blocks, the second set of metadata encrypted using the second encryption key, setting the second encryption key as the current encryption key for the plurality of memory blocks.
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23. A storage device, comprising:
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a plurality of memory blocks including a first set of memory blocks and a second set of memory blocks, wherein the second set of memory blocks does not comprise any memory block in the first set of memory blocks, the first set of memory blocks storing a first set of metadata and the second set of memory blocks storing a second set of metadata; an interface for coupling the storage device to a host system; and a controller having one or more processors, an encryption module, and a first encryption key established as a current encryption key, the controller configured to perform a power-failure tolerant cryptographic erase operation to erase data stored in the storage device by; obtaining and storing a second encryption key; storing, in the first set of memory blocks, the second set of metadata encrypted with the second encryption key; subsequent to storing, in the first set of memory blocks, the second set of metadata encrypted with the second encryption key, storing the second set of metadata encrypted with the second encryption key at corresponding locations in the second set of memory blocks; storing the first set of metadata encrypted with the second encryption key in the first set of memory blocks; and establishing the second encryption key as the current encryption key to encrypt metadata and data, if any, in at least the first and second sets of memory blocks, wherein performing the cryptographic erase operation further comprises; storing in non-volatile memory a progress indicator that indicates a stage of the cryptographic erase operation, and updating the progress indicator upon completion of each stage of a predefined set of stages of the cryptographic erase operation; determining whether a power failure has occurred while performing the cryptographic erase operation; and in accordance with a determination that a power failure has occurred while performing the cryptographic erase operation, resuming performance of the cryptographic erase operation at a stage corresponding to a value of the progress indicator. - View Dependent Claims (24, 25)
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26. A non-transitory computer readable storage medium, storing one or more programs for execution by one or more processors of a storage device, the storage device having a plurality of memory blocks including a first set of memory blocks and a second set of memory blocks, wherein the second set of memory blocks does not comprise any memory block in the first set of memory blocks, the one or more programs including instructions for performing a power-failure tolerant cryptographic erase operation to erase data stored in the storage device by:
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accessing, in the storage device, data previously encrypted using a first encryption key; obtaining and storing a second encryption key; storing, in the first set of memory blocks, a first set of metadata corresponding to the first set of memory blocks, encrypted using the second encryption key; and storing, in the first set of memory blocks, a second set of metadata corresponding to the second set of memory blocks, encrypted using the second encryption key; subsequent to storing, in the first set of memory blocks, the second set of metadata encrypted with the second encryption key, storing the second set of metadata encrypted with the second encryption key at corresponding locations in the second set of memory blocks; storing the first set of metadata encrypted with the second encryption key in the first set of memory blocks; and establishing the second encryption key as the current encryption key to encrypt metadata and data, if any, in at least the first and second sets of memory blocks, wherein performing the cryptographic erase operation further comprises; storing in non-volatile memory a progress indicator that indicates a stage of the cryptographic erase operation, and updating the progress indicator upon completion of each stage of a predefined set of stages of the cryptographic erase operation; determining whether a power failure has occurred while performing the cryptographic erase operation; and
,in accordance with a determination that a power failure has occurred while performing the cryptographic erase operation, resuming performance of the cryptographic erase operation at a stage corresponding to a value of the progress indicator. - View Dependent Claims (27, 28)
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29. A storage device, comprising:
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a plurality of memory blocks including a first set of memory blocks and a second set of memory blocks, wherein the second set of memory blocks does not comprise any memory block in the first set of memory blocks; an interface for coupling the storage device to a host system; and a controller having one or more processors, an encryption module, and a first encryption key established as a current encryption key, the controller configured to perform a power-failure tolerant cryptographic erase operation to erase data stored in the storage device by; performing a set of first stage operations, including; obtaining a second encryption key; performing a set of second stage operations, including; erasing data stored in the first set of memory blocks; storing, in the first set of memory blocks, a first set of metadata corresponding to the first set of memory blocks, encrypted using the second encryption key; and storing, in the first set of memory blocks, a second set of metadata corresponding to the second set of memory blocks, encrypted using the second encryption key; and performing a set of third stage operations, including; erasing data stored in the second set of memory blocks; and storing, in the second set of memory blocks, the second set of metadata encrypted using the second encryption key; and subsequent to storing, in the second set of memory blocks, the second set of metadata encrypted using the second encryption key, setting the second encryption key as the current encryption key for the plurality of memory blocks; wherein performing the cryptographic erase operation further comprises; storing in non-volatile memory a progress indicator that indicates a stage of the cryptographic erase operation, and updating the progress indicator upon completion of each stage of a predefined set of stages of the cryptographic erase operation; determining whether a power failure has occurred while performing the cryptographic erase operation; and in accordance with a determination that a power failure has occurred while performing the cryptographic erase operation, resuming performance of the cryptographic erase operation at a stage corresponding to a value of the progress indicator. - View Dependent Claims (30)
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Specification