Seagate BarraCuda Product Manual, Rev. D
26
About (SED) Self-Encrypting Drives
4.0 About (SED) Self-Encrypting Drives
Self-encrypting drives (SEDs) offer encryption and security services for the protection of stored data, commonly known as
"data at rest". These drives are compliant with the Trusted Computing Group (TCG) Opal Storage Specifications as detailed
in the following:
•
TCG Storage Architecture Core Specification, Version 2.0 (see
www.trustedcomputinggroup.org
)
•
TCG Storage Security Subsystem Class Opal Specification, Version 2.0 (see
www.trustedcomputinggroup.org
)
In case of conflict between this document and any referenced document, this document takes precedence.
The Trusted Computing Group (TCG) is a standards organization sponsored and operated by companies in the computer,
storage 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 SATA
commands:
•
Trusted Send
•
Trusted Receive
These commands are used to convey the TCG protocol to and from the drive in their command payloads. Seagate Secure SEDs also
support TCG Single User Mode, which can be disabled.
4.1
Data Encryption
Encrypting drives use one inline encryption engine within each drive employing AES-256 algorithms 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 engine
is 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
in volatile temporary storage (DRAM), which is external to the encryption engine. A unique data encryption key is used for each of the
drive's possible16 data bands (see
4.2
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 the user provides the correct credentials to prove that they are
authorized to perform the command.
4.2.1 Admin SP
The Admin SP allows the drive's owner to enable or disable firmware download operations (see
). Access to
the Admin SP is available using the SID (Secure ID) password.
4.2.2 Locking SP
The Locking SP controls read/write access to the media and the cryptographic erase feature. Access to the Locking SP is available using
the Admin or User passwords.
4.2.3 Default password
When the drive is shipped from the factory, all passwords are set to the value of MSID. This 32-byte random value can only be read by the
host electronically over the interface. After receipt of the drive, it is the responsibility of the owner to use the default MSID password as
the authority to change all other passwords to unique owner-specified values.
4.2.4 ATA Enhanced Security
The drive can utilize the system's BIOS through the ATA Security API for cases that do not require password management and additional
security policies.
Furthermore, the drive's ATA Security Erase Unit command shall support both Normal and Enhanced Erase modes with the following
modifications/additions:
Normal Erase:
Normal erase feature shall be performed by changing the Data Encryption Key (DEK) of the drive, followed by an
overwrite operation that repeatedly writes a single sector containing random data to the entire drive. This write operation bypasses the
media encryption. On reading back the overwritten sectors, the host will receive a decrypted version, using the new DEK of the random
data sector (the returned data will not match what was written).
Enhanced Erase:
Enhanced erase shall be performed by changing the Data Encryption Key of the drive.
4.3
Random Number Generator (RNG)
The drive has a 32-byte hardware RNG that it is uses to derive encryption keys or, if requested to do so, to provide random numbers to
the host for system use, including using these numbers as Authentication Keys (passwords) for the drive's Admin and Locking SPs.
