Memory system and method of controlling nonvolatile memory

1. A memory system, comprising:

a nonvolatile memory; and

a controller electrically connected to the nonvolatile memory and configured to:

in response to receiving, from a host, a write request that specifies a first physical address, select a first encryption key from a plurality of encryption keys, and encrypt data using the first physical address and the selected first encryption key, and write the encrypted data to a first physical storage location of the nonvolatile memory that is designated by the first physical address; and

when the encrypted data is to be copied from the first physical storage location to a second physical storage location of the nonvolatile memory, decrypt the encrypted data using the first physical address and the first encryption key, select a second encryption key from the plurality of encryption keys, and re-encrypt the decrypted data using the selected second encryption key and a copy destination physical address indicative of the second physical storage location, and write the re-encrypted data to the second physical storage location.

2. The memory system of claim 1 , wherein the controller is further configured to:

manage correspondence between the plurality of encryption keys and a plurality of regions obtained by logically dividing the nonvolatile memory;

select an encryption key associated with a first region to which the first physical storage location belongs, as the first encryption key; and

select an encryption key associated with a second region to which the second physical storage location belongs, as the second encryption key.

3. The memory system of claim 1 , wherein

the nonvolatile memory includes a plurality of blocks, and

the controller is further configured to:

manage correspondence between the plurality of encryption keys and the plurality of blocks;

select an encryption key associated with a first block to which the first physical storage location belongs, as the first encryption key; and

select an encryption key associated with a second block to which the second physical storage location belongs, as the second encryption key.

4. The memory system of claim 1 , wherein

the controller is further configured to, in response to receiving, from the host, a copy request to designate the first physical address as a copy source physical address and to designate a second physical address as the copy destination physical address, execute an operation of decrypting the encrypted data using the first encryption key and the first physical address, an operation of re-encrypting the decrypted data using the second encryption key and the second physical address, and an operation of writing the re-encrypted data to the second physical storage location.

5. A memory system connectable to a host, comprising:

a nonvolatile memory including a plurality of blocks; and

a controller electrically connected to the nonvolatile memory and configured:

in response to receiving, from the host, a write request to designate a first physical address indicative of a first physical storage location in a first block of the nonvolatile memory to which data is to be written, select a first encryption key from a plurality of encryption keys, and encrypt the data using the first physical address and the selected first encryption key and write the encrypted data to the first physical storage location in the first block;

in response to receiving, from the host, a read request to designate the first physical address, read the encrypted data from the first block and decrypt the read encrypted data using the first physical address and the first encryption key; and

in response to receiving, from the host, a copy request to designate a copy source physical address indicative of the first physical storage location in the first block and a copy destination physical address indicative of a second physical storage location in a second block of the nonvolatile memory, read the encrypted data from the first block, decrypt the read encrypted data using the copy source physical address and the first encryption key, select a second encryption key from the plurality of encryption keys, and re-encrypt the decrypted data using the copy destination physical address and the selected second encryption key, and write the re-encrypted data to the second physical storage location in the second block.

6. The memory system of claim 5 , wherein the controller is further configured to:

manage correspondence between the plurality of encryption keys and a plurality of regions obtained by logically dividing the nonvolatile memory, each of the write request and the read request further designating an identifier indicative of one of the plurality of regions,

in response to receiving the write request, select an encryption key associated with a region indicated by the identifier designated by the write request, as the first encryption key,

in response to receiving the read request, select the encryption key associated with the region indicated by the identifier designated by the read request, as the first encryption key, and

in response to receiving the copy request, select an encryption key associated with a region to which the second block designated by the copy destination physical address belongs, as the second encryption key.

7. The memory system of claim 5 , wherein the controller is further configured to:

manage correspondence between the plurality of encryption keys and the plurality of blocks, the first physical address designated by each of the write request and the read request including a block address indicative of the first block and an in-block physical address indicative of the first physical storage location in the first block, the copy destination physical address including a block address indicative of the second block and an in-block physical address indicative of the second physical storage location in the second block;

in response to receiving the write request, select an encryption key associated with the first block as the first encryption key, based on the block address designated by the write request;

in response to receiving the read request, select the encryption key associated with the first block as the first encryption key, based on the block address designated by the read request; and

in response to receiving the copy request, select an encryption key associated with the second block as the second encryption key, based on the block address designated by the copy request.

8. A method of controlling a nonvolatile memory, the method comprising:

in response to receiving, from a host, a write request that specifies a first physical address, selecting a first encryption key from a plurality of encryption keys, and executing an operation of encrypting data using the first physical address and the selected first encryption key, and an operation of writing the encrypted data to a first physical storage location of the nonvolatile memory that is designated by the first physical address; and

when the encrypted data is to be copied from the first physical storage location to a second physical storage location of the nonvolatile memory, executing an operation of decrypting the encrypted data using the first physical address and the first encryption key, selecting a second encryption key from the plurality of encryption keys, and executing an operation of re-encrypting the decrypted data using the selected second encryption key and a copy destination physical address indicative of the second physical storage location, and an operation of writing the re-encrypted data to the second physical storage location.

9. The method of claim 8 , further comprising:

managing correspondence between the plurality of encryption keys and a plurality of regions obtained by logically dividing the nonvolatile memory;

selecting an encryption key associated with a first region to which the first physical storage location belongs, as the first encryption key; and

selecting an encryption key associated with a second region to which the second physical storage location belongs, as the second encryption key.

10. The method of claim 8 , wherein the nonvolatile memory includes a plurality of block, and

the method further comprises:

managing correspondence between the plurality of encryption keys and the plurality of blocks;

selecting an encryption key associated with a first block to which the first physical storage location belongs, as the first encryption key; and

selecting an encryption key associated with a second block to which the second physical storage location belongs, as the second encryption key.

11. The method of claim 8 , wherein

the operation of decrypting the encrypted data, the operation of re-encrypting the decrypted data, and the operation of writing the re-encrypted data to the second physical storage location are executed in response to receiving, from the host, a copy request to designate the first physical address as a copy source physical address and to designate a second physical address as the copy destination physical address.