0xEEEE - Send Secured Command to Device
The host uses this command to transmit another command securely. This “secure wrapper” mechanism provides the device a means to ensure the wrapped command originated from an authentic, authorized host. In addition, its implementation includes an operation that starts a countdown timer, which ensures the command is current and is not an unauthorized replay of a previously intercepted / stored command. This command can use multiple authentication methods, including MAC or ECDSA Signature. The method and parameters to use are specific to the command being wrapped, and are specified in the documentation for that command.
The sequence of events is as follows:
Retrieve Challenge Token
The host uses Get Challenge - Command 0xE001 to retrieve a Challenge Token and unlock the device for receiving the desired command for a limited period of time. When the time expires, the device will no longer accept the Challenge Token and the host will have to retrieve another one.
Build the 0xEEEE request
The host creates an instance of Send Secured Command to Device - Command 0xEEEE in the format below and includes the Message Payload and Challenge Token inside it. In the Request Message, it fills in Command ID as the command number of the wrapped Message Payload, instead of 0xEEEE. Some parameters are command-specific; see the documentation for the command that is being wrapped to determine what values to use.
Request Data for Send Secured Command to Device - Command 0xEEEE
Beginning of any wrappers, at minimum including Request Message
EEEE = Send Secured Command to Device - Command 0xEEEE
A1
var
Security Parameters — This parameter describes how the Signature parameter in this data object is calculated, and is a Security Parameters Type TLV data object. To determine which values to use in that TLV data object, see the documentation for the command being wrapped.
T
R
82
04
Serial Number
B
R
83
08
Challenge Token — The token the device returned when the host called Get Challenge - Command 0xE001.
B
R
84
var
Message Payload
B
R
9E
var
MAC or Signature
B
R
End of any wrappers, at minimum including Request Message
Request Example Using MAC
Example (Hex):
This example wraps [**Command 0xD811 - Start Send File to Device (Secured)
AA 00 81 04 01 04 D8 11 84 81 8F EE EE A1 19 81 05 03 03 06 02 08 84 00 85 00 A8 0A 81 02 11 02 82 00 86 00 88 00 A9 00 82 04 FF FF FF F0 83 08 C9 65 45 F2 97 69 85 B1 84 4E D8 11 81 04 00 00 03 00 A2 2B 81 04 00 00 02 99 82 01 04 83 20 87 A4 B3 54 61 C5 CB D3 1D DC BA 9D 65 25 5A D4 6A 22 FA 51 5E FD 65 87 AF AC A8 8C 4F AF 80 9B A3 14 38 31 30 38 33 30 33 30 33 30 33 30 33 33 33 30 33 30 87 01 01 9E 10 7D E4 27 C8 A0 70 72 08 19 0A 1E 0A 3F 48 BB F1Request Example Using ECDSA
Last updated