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7.5
Data bands
When shipped from the factory, the drive is configured with a single data band called Band 0 (also known as the Global Data Band) which comprises
LBA 0 through LBA max. The host may allocate Band1 by specifying a start LBA and an LBA range. The real estate for this band is taken from the
Global Band. An additional 14 Data Bands may be defined in a similar way (Band2 through Band15) but before these bands can be allocated LBA
space, they must first be individually enabled using the EraseMaster password.
Data bands cannot overlap but they can be sequential with one band ending at LBA (x) and the next beginning at LBA (x+1).
Each data band has its own drive-generated encryption key and its own user-supplied password. The host may change the Encryption Key (see
Section 7.6) or the password when required. The bands should be aligned to 4K LBA boundaries.
7.6
Cryptographic erase
A significant feature of SEDs is the ability to perform a cryptographic erase. This involves the host telling the drive to change the data encryption key
for a particular band. Once changed, the data is no longer recoverable since it was written with one key and will be read using a different key. Since
the drive overwrites the old key with the new one, and keeps no history of key changes, the user data can never be recovered. This is tantamount to
an instantaneous data erase and is very useful if the drive is to be scrapped or redispositioned. The Sanitize or TCG erase method can be invoked to
cryptographically erase all user data on the drive by destroying the current data encryption key and replacing it with a new random drive-
generated encryption key. Sanitize CRYPTOGRAPHIC ERASE is a SCIS CDB Op Code 48h and service action code 3 (CRYPTOGRAPHIC ERASE).
7.7
Authenticated firmware download
In addition to providing a locking mechanism to prevent unwanted firmware download attempts, the drive also only accepts download files which
have been cryptographically signed by the appropriate Seagate Design Center.
Three conditions must be met before the drive will allow the download operation:
1.
The download must be an SED file. A standard (base) drive (non-SED) file will be rejected.
2.
The download file must be signed and authenticated.
3.
As with a non-SED drive, the download file must pass the acceptance criteria for the drive. For example it must be applicable to the correct
drive model, and have compatible revision and customer status.
4.
The firmware download port must be unlocked. When the drive is shipped from the factory, the firmware download port is unlocked.
7.8
Power requirements
The standard drive models and the SED drive models have identical hardware, however the security and encryption portion of the drive controller
ASIC is enabled and functional in the SED models. This represents a small additional drain on the 5V supply of about 10mA and a commensurate
increase of about 50mW in power consumption. There is no additional drain on the 12V supply. See the tables in Section 6.3 for power requirements
on the standard (non-SED) drive models.
7.9
Supported commands
The SED models support the following two commands in addition to the commands supported by the standard (non-SED) models as listed in Table
5:
• Security Protocol Out (B5h)
• Security Protocol In (A2h)
7.10
RevertSP
SED models will support the RevertSP feature which erases all data in all bands on the device and returns the contents of all SPs (Security Providers)
on the device to their original factory state. In order to execute the RevertSP method the unique PSID (Physical Secure ID) printed on the drive label
must be provided. PSID is not electronically accessible and can only be manually read from the drive label or scanned in via the 2D barcode.
RevertSP can be used to recover the use of drives when the passwords are lost.
Seagate Enterprise Performance - 3.5 HDD SAS Product Manual, Rev. B
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