Security User Guide: Intel® FPGA Programmable Acceleration Card D5005

ID 683877
Date 8/25/2020
Public

2.2. Anti-Rollback Capability

The Intel® MAX® 10 BMC RoT provides anti-rollback capability through the code signing key ID cancellation feature. A CSK is assigned an ID, a number between 0-31, during the signing process. CSK ID cancellation information is stored in 32-bit fields in write-once locations in flash. When a code signing key ID is canceled, the Intel® MAX® 10 BMC RoT rejects all signatures created with a CSK that is assigned that ID. If a CSK ID that is used in an old update is canceled after applying a new update with a different CSK ID, the Intel® MAX® 10 BMC RoT rejects the signature of the old update, preventing a rollback to the old update.

Note: If you cancel a key and do not update your image with a different CSK ID, the old image continues to be operational unless the user updates it with the new image signed with a different CSK ID.