Abstract: A memory system includes a nonvolatile memory including user areas, a volatile memory, a battery, and a controller configured to, when the volatile memory maintains first information indicating an access to a user area is permitted and a verification value upon startup of the system, determine whether the information is validated by the value, and upon determining that the information is validated, permit an access to the user area and prohibit the access to any other area, and when the volatile memory does not maintain the information and value, or the information is not validated, prohibit an access to any user area, and thereafter, upon receipt of a command and authentication information from the host, permit an access to the user area requested by the command, and generate and store in the volatile memory the information and the value for validating the generated information.

Abstract: A memory system includes a nonvolatile memory including user areas, a volatile memory, a battery, and a controller configured to, when the volatile memory maintains first information indicating an access to a user area is permitted and a verification value upon startup of the system, determine whether the information is validated by the value, and upon determining that the information is validated, permit an access to the user area and prohibit the access to any other area, and when the volatile memory does not maintain the information and value, or the information is not validated, prohibit an access to any user area, and thereafter, upon receipt of a command and authentication information from the host, permit an access to the user area requested by the command, and generate and store in the volatile memory the information and the value for validating the generated information.

Abstract: According to embodiments, a storage device includes a storage unit, a receiving unit, an authenticating unit, and a control unit. Prior to executing erasure processing of data that has been stored in the storage unit, the receiving unit receives, from an external device that clocks time, third information including first information and second information, the first information regarding time counted by the external device and the second information being information for authenticating the external device. The authenticating unit performs authentication processing of the external device by using the second information included in the third information. When the authentication of the external device has succeeded, the control unit generates an erasure log that contains erasure time when the erasure processing has been executed on the basis of the first information included in the third information. When the authentication of the external device has failed, the execution of the erasure processing is prohibited.