3.3.2.2 Compatibility of Firmware Revisions

Warning: The firmware upgrade might be non-reversible. The following section provides important details.

The nCipher HSM module firmware has two versioning characteristics:

Firmware revision number
Version Security Number (VSN)

The firmware revision number identifies the individual version of the firmware, while the VSN can group multiple revisions together and is used to restrict revision downgrade, so that the intruders cannot move a module to the firmware with known security issues. The downgrade is possible to any firmware revision with the same VSN as the one in the module. The upgrade can be done to any revision with the same or higher VSN number.

Information about firmware revisions and their respective VSN numbers is available on the Security World installation media of firmware upgrade media, distributed as part of nCipher security advisories.