TRUSTED
RECEIVE (5Ch), PIO Data-In
This 28-bit command is mandatory for
devices implementing the Trusted Computing feature set.
The TRUSTED RECEIVE command is used to
retrieve security protocol information or the results from one or more TRUSTED
SEND commands.
Any association between a previous TRUSTED
SEND command and the data transferred by a TRUSTED RECEIVE command depends on
the protocol specified by the Security Protocol field. If the device has no
data to transfer (e.g., the results for any previous TRUSTED SEND commands are
not yet available), the device may transfer data indicating it has no other
data to transfer.
Indications of data overrun or underrun and
the mechanism, if any, for processing retries depend on the protocol specified
by the Security Protocol field. For Security Protocol field set to 00h, the format
of the data is described in. The format of the data for other Security Protocol
values is documented by the group that owns the associated Security Protocol
value. The device shall retain data resulting from a TRUSTED SEND command
awaiting retrieval by a TRUSTED RECEIVE command until one of the following
events is processed:
A.
the data is delivered according
to the Security Protocol field (see
table 67) specific rules for the TRUSTED RECEIVE command;
B.
any reset; or
C.
loss of communication with the
host that sent the TRUSTED SEND command.
Inputs:
|
Register
|
7
|
6
|
5
|
4
|
3
|
2
|
1
|
0
|
|
Feature
|
Security
Protocol
|
|
Sector
Count
|
Transfer
Length (7:0)
|
|
LBA
Low(7:0)
|
Transfer
Length (15:8)
|
|
LBA
Mid(15:8)
|
SP
Specific(7:0) - Security Protocol Specific
|
|
LBA
High(23:16)
|
SP
Specific(15:8) - Security Protocol Specific
|
|
Device
|
obs
|
N/A
|
obs
|
TD
|
LBA(27:24)
Reserved
|
|
Command
|
5Ch
|
Transfer
Length:The Transfer Length is security protocol
specific
TD: Transport Dependent - All bits and fields that are labelled
transport dependent are defined in the transport standards.
Generic
Extended Normal Outputs:
|
Register
|
7
|
6
|
5
|
4
|
3
|
2
|
1
|
0
|
|
Error
|
Reserved
|
|
Sector
Count
|
HOB
= 0
|
Reserved
|
|
HOB
= 1
|
Reserved
|
|
LBA
Low
|
HOB
= 0
|
Reserved
|
|
HOB
= 1
|
Reserved
|
|
LBA
Mid
|
HOB
= 0
|
Reserved
|
|
HOB
= 1
|
Reserved
|
|
LBA
High
|
HOB
= 0
|
Reserved
|
|
HOB
= 1
|
Reserved
|
|
Device
|
obs
|
na
|
obs
|
TD
|
Reserved
|
|
Status
|
TD
|
TD
|
DF
|
na
|
TD
|
na
|
na
|
ERR
|
Security Protocol
The Security Protocol field identifies
which security protocol is being used. This determines the format of the SP
Specific field and of the data that is transferred. If the Security Protocol
field is set to a reserved value, the device shall return command aborted.
TRUSTED
RECEIVE Security Protocol field description table
|
Value
|
Description
|
|
00h
|
Return security protocol information
|
|
01h – 06h
|
Defined by TCG
|
|
07h – 1Fh
|
Reserved
|
|
20h
|
Reserved for T10
|
|
21h-EDh
|
Reserved
|
|
EEh
|
Defined by IEEE 1667
|
|
EFh
|
Reserved for T10
|
|
F0h – FFh
|
Vendor Specific.
|
The meaning of the SP Specific field is
defined by each security protocol.
Security Protocol 00h - SP
Specific field descriptions for Protocol 00h
|
SP Specific
|
Description
|
Support
|
|
0000h
|
Return supported security protocol list
|
Mandatory
|
|
0001h
|
Return a certificate
|
Mandatory
|
|
0002h-FFFFh
|
Reserved
|
|
Supported
security protocols list description
When the Security Protocol field is set to
00h, and SP Specific is set to 0000h in a TRUSTED RECEIVE command, the
parameter data shall have the format shown in table.
|
byte bit
|
7
|
6
|
5
|
4
|
3
|
2
|
1
|
0
|
|
0
|
Reserved
|
|
1
|
Reserved
|
|
2
|
Reserved
|
|
3
|
Reserved
|
|
4
|
Reserved
|
|
5
|
Reserved
|
|
6
|
List
Length (M-7) bits (15:8)
|
|
7
|
List
Length (M-7) bits (7:0)
|
|
8
|
Supported
Security Protocol List
|
|
|
|
M
|
|
M+1
|
Pad
bytes (if any)
|
|
511
|
The List Length field indicates the total
length, in bytes, of the supported security protocol list.
The Supported Security Protocol List field
shall contain a list of all supported Security Protocol field values. Each byte
indicates a supported Security Protocol field value. The values shall be in ascending order
starting with 00h.
The total data length shall be 512 bytes.
Pad bytes are appended as needed to meet this requirement. Pad bytes shall have
a value of 00h.
Certificate
data description
A certificate is either an X.509 Attribute
Certificate or an X.509 Public Key Certificate depending on the capabilities of
the device.
When the Security Protocol field of the
TRUSTED RECEIVE command is set to 00h, and SP Specific is 0001h, the parameter
data shall have the format shown in table 70.
|
byte bit
|
7
|
6
|
5
|
4
|
3
|
2
|
1
|
0
|
|
0
|
Reserved
|
|
1
|
Reserved
|
|
2
|
(MSB) CERTIFICATE LENGTH (M - 3)
(LSB)
|
|
3
|
|
4
|
X.509
certificate bytes
|
|
|
|
M
|
|
M+1
|
Pad
bytes (if any)
|
|
511
|
The CERTIFICATE LENGTH indicates the total
length, in bytes, of the certificate(s).
This length includes one or more certificates. If the device has no
certificate to return, the certificate length is set to 0000h and only the 4
byte header and 508 pad bytes are returned.
The total data length shall conform to the
Transfer Length field requirements.
Public
Key certificate description
RFC 3280 defines the certificate syntax for
certificates consistent with the X.509v3 Public Key Certificate Specification.
Attribute
certificate description
RFC 3281 defines the certificate syntax for
certificates consistent with the X.509v2 Attribute Certificate Specification.
In the IDENTIFY DEVICE data of Word48:
|
Word
|
OM
|
SP
|
FV
|
Description
|
|
48
|
O
|
B
|
F
F
F
|
Trusted Computing feature set options
15
Shall be cleared to zero
14
Shall be set to one
13:1
Reserved for the Trusted Computing Group
0
1=Trusted Computing feature set is supported
|
