# US 8,751,802 B2 · Storage device and method and for storage device state recovery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,751,802 B2 - Document ID: US8751802B2 - Status: Granted - Kind: B2 - Application number: 12/827,978 - Filed: 2010-06-30 - Published: 2012-01-05 - Granted: 2014-06-10 - Earliest claimed: 2010-06-30 - Assignees: SanDisk IL Ltd. - Applicants: Rotem Sela; Avraham Shmuel - Inventors: Rotem Sela; Avraham Shmuel - Web page: https://patentgrep.com/patent/US8751802B2 ## CPC - G06F 21/445: {by mutual authentication, e.g. between devices or programs} - G06F 21/78: to assure secure storage of data (address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A storage device and method for storage device state recovery are provided. In one embodiment, a storage device commences an authentication process to authenticate a host device. The authentication process comprises a plurality of phases, and the storage device stores the state of the authentication process, wherein the state indicates the phase(s) of the authentication process that have been successfully completed. After a power loss, the storage device retrieves the state of the authentication process and resumes an operation with the host device without re-performing the phase(s) of the authentication process that have been completed. ## Claims ### Claim 1 A method for storage device recovery, the method comprising: performing the following in a storage device: commencing an authentication process to authenticate a host device, wherein the authentication process comprises a plurality of phases; storing a state of the authentication process, wherein the state indicates the phase(s) of the authentication process that have been successfully completed; after a power loss, receiving a recovery command from the host device; determining if the recovery command indicates that the host device is a pre-authenticated entity; if the storage device determines that the recovery command indicates that the host device is a pre-authenticated entity: retrieving the state of the authentication process; and resuming an operation with the host device without re-performing the phase(s) of the authentication process that have been completed; and if the storage device determines that the recovery command does not indicate that the host device is a pre-authenticated entity, operating in a blocked state that indicates a failure to log in. ### Claim 2 (depends on 1) The method of claim 1, wherein when the state indicates that all phases of the authentication process have been successfully completed, the operation with the host device resumes without requiring the host device to re-authenticate itself to the storage device. ### Claim 3 (depends on 1) The method of claim 1, wherein the state is stored in a location in the storage device that is accessible by a controller of the storage device but not by the host device. ### Claim 4 (depends on 1) The method of claim 1, wherein the state is stored automatically by the storage device. ### Claim 5 (depends on 1) The method of claim 1, wherein the state is stored in response to a command from the host device. ### Claim 6 (depends on 1) The method of claim 1 further comprising operating in a logged-off state if the recovery command is not received. ### Claim 7 (depends on 1) The method of claim 1, wherein the recovery command comprises a secure token. ### Claim 8 (depends on 7) The method of claim 7, wherein the secure token comprises a function of a session key. ### Claim 9 (depends on 8) The method of claim 8, wherein the secure token is also a function of a value of a counter. ### Claim 10 (depends on 7) The method of claim 7, wherein the secure token comprises a function of a session ID. ### Claim 11 (depends on 10) The method of claim 10, wherein the secure token is also a function of a value of a counter. ### Claim 12 (depends on 1) The method of claim 1, wherein the recovery command is received from a different, but previously-authenticated, host device. ### Claim 13 A storage device comprising: an interface configured to communicate with a host device; a memory; and a controller in communication with the interface and the memory, wherein the controller is configured to: commence an authentication process to authenticate a host device, wherein the authentication process comprises a plurality of phases; store a state of the authentication process, wherein the state indicates the phase(s) of the authentication process that have been successfully completed; after a power loss, receive a recovery command from the host device; determine if the recovery command indicates that the host device is a pre-authenticated entity; if the storage device determines that the recovery command indicates that the host device is a pre-authenticated entity: retrieve the state of the authentication process; and resume an operation with the host device without re-performing the phase(s) of the authentication process that have been completed; and if the storage device determines that the recovery command does not indicate that the host device is a pre-authenticated entity, operate in a blocked state that indicates a failure to log in. ### Claim 14 (depends on 13) The storage device of claim 13, wherein when the state indicates that all phases of the authentication process have been successfully completed, the operation with the host device resumes without requiring the host device to re-authenticate itself to the storage device. ### Claim 15 (depends on 13) The storage device of claim 13, wherein the state is stored in a location in the memory that is accessible by the controller of the storage device but not by the host device. ### Claim 16 (depends on 13) The storage device of claim 13, wherein the state is stored automatically by the controller. ### Claim 17 (depends on 13) The storage device of claim 13, wherein the state is stored in response to a command from the host device. ### Claim 18 (depends on 13) The storage device of claim 13, wherein the controller is configured to operate in a logged-off state if the recovery command is not received. ### Claim 19 (depends on 13) The storage device of claim 13, wherein the recovery command comprises a secure token. ### Claim 20 (depends on 19) The storage device of claim 19, wherein the secure token comprises a function of a session key. ### Claim 21 (depends on 20) The storage device of claim 20, wherein the secure token is also a function of a value of a counter. ### Claim 22 (depends on 19) The storage device of claim 19, wherein the secure token comprises a function of a session ID. ### Claim 23 (depends on 22) The storage device of claim 22, wherein the secure token is also a function of a value of a counter. ### Claim 24 (depends on 13) The storage device of claim 13, wherein the recovery command is received from a different, but previously-authenticated, host device.