User Manual

Constellation.2 SAS Product Manual, Rev. K 46
8.0 About self-encrypting drives
Self-encrypting drives (SEDs) offer encryption and security services for the protection of stored data, commonly
known as “protection of data at rest.” These drives are compliant with the Trusted Computing Group (TCG) Enterprise
Storage Specifications as detailed in Section 2.2.
The Trusted Computing Group (TCG) is an organization sponsored and operated by companies in the computer, stor-
age and digital communications industry. Seagate’s SED models comply with the standards published by the TCG.
To use the security features in the drive, the host must be capable of constructing and issuing the following two SCSI
commands:
• Security Protocol Out
• Security Protocol In
These commands are used to convey the TCG protocol to and from the drive in their command payloads.
8.1 Data encryption
Encrypting drives use one inline encryption engine for each port, employing AES-128 data encryption in Cipher Block
Chaining (CBC) mode to encrypt all data prior to being written on the media and to decrypt all data as it is read from
the media. The encryption engines are always in operation and cannot be disabled.
The 32-byte Data Encryption Key (DEK) is a random number which is generated by the drive, never leaves the drive,
and is inaccessible to the host system. The DEK is itself encrypted when it is stored on the media and when it is in vol-
atile temporary storage (DRAM) external to the encryption engine. A unique data encryption key is used for each of
the drive's possible16 data bands (see Section 8.5).
8.2 Controlled access
The drive has two security providers (SPs) called the "Admin SP" and the "Locking SP." These act as gatekeepers to the
drive security services. Security-related commands will not be accepted unless they also supply the correct credentials
to prove the requester is authorized to perform the command.
8.2.1 Admin SP
The Admin SP allows the drive's owner to enable or disable firmware download operations (see Section 8.4). Access to
the Admin SP is available using the SID (Secure ID) password or the MSID (Manufacturers Secure ID) password.