Command 0X50 - Fixed Key Authentication Response (Fixed Key Only) - Magtek mDynamo Programmer's Manual

7 - Commands

7.3.10 Command 0x50 - Fixed Key Authentication Response (Fixed Key Only)

The host uses this command, along with Command 0x4F - Fixed Key Authentication Challenge (Fixed
Key Only), to authenticate before calling Command 0x4E - Load Fixed Key (Fixed Key Only) if that
command has previously configured the device to require authentication for loading subsequent fixed
keys. Performing this sequence successfully proves to the device that the host has knowledge of the
current fixed key value.
The host should first call Command 0x4F - Fixed Key Authentication Challenge (Fixed Key Only).
The device encrypts a random string using the current fixed key, and sends the resulting encrypted 8-byte
challenge in its response to the host. The host should then decrypt the challenge using the current fixed
key, and send the first four bytes back to the device using this command.
If the Authentication Response field matches the first 4 bytes of the random string the device used,
authentication succeeds, otherwise it fails. The result code indicates if it succeeded or failed.
If successful, the device remains in authenticated mode until it is power cycled/reset or until it receives
another Command 0x4F - Fixed Key Authentication Challenge (Fixed Key Only).
Table 7-18 - Request Data for Command 0x50 - Fixed Key Authentication Response (Fixed Key Only)
Offset
0 - 3 Authentication Response
Response Data: None
Result codes:
0x00 = Success
0x01 = Failure
0x02 = Bad Parameter
Example Request (Hex)
Cmd Num Data Len
50 04
Example Response (Hex)
Result Code
00
mDynamo| OEM Secure Card Reader Authenticator | Programmer's Manual (COMMANDS)
Field Name
371B5A89 (Challenge 5B0BF27FCDB6C280 is decrypted under the
current key of all zeroes)
Data Len
00
Page 55 of 167 (D998200151-200)
Description
First four bytes of the unencrypted
Authentication Challenge
Data
Data