Specifications

Print Controller Design Guide for Information Security:
Page 14 of 92
• This use of a public key to decrypt the digital signature allows the MFP/LP to verify that that there has
been no illegal alteration of the data.
• The basic identifying information of the firmware (version, type, etc.) is stored in the MFP/LP as the
update is being performed. Therefore it is possible to retry the update with the same SD card in the
event that the update is interrupted, e.g. if the MFP/LP main power suddenly turns off. After recovery is
initiated, the MFP/LP checks to see that the data in the SD card has not been altered, and then
resumes the update.
Digital
signature
Program
3. Generate MD1
using SHA-1
MD1
MD2
Public key
4. Decryption
5. Compare MD1
and MD2
If MD1 ≠ MD2
Update process is cancelled
and new firmware is not
installed
If MD1 = MD2
2. Verification of firmware version
6. Firmware is overwritten
with new files
1. Verification of model and target
machine functions (Copier, Printer,
etc.)
Ricoh License Server
Digital signature
2. Generate
digital signature
Program
1. Generate MD
using SHA-1
MD
3. Files are sent
Private key
SDSD
6464MBMB
SDSD
6464MBMB
SD card
"MD": Message Digest
Firmware Installation Using an SD Card