Mr. Pat Larkin:

It is still slow; it is not instantaneous. It would definitely assist if there were data compromised for which there is no viable backup. If the keys are not a trick or duplicitous, there is potentially a model by which data that are not otherwise accessible can be recovered. With regard to the restoration process, the technology that these guys provide is slow by default, particularly where the operation is at scale. A recovery-and-rebuild process has to be undergone anyway. It is a question of whether restoring the data from backup, assuming the HSE has viable and accessible backups, is more efficient than decrypting the systems in play. In most cases, it will not be a job of simply decrypting restore systems.