I inherited VeeamOne with an already existing infrastructure, and I appreciate it more every day
About the checksum, I have read "When writing each data block to the disk, we also write a checksum of this block to the designated area of the backup file (actually, we write the checksum twice for redundancy). When restoring, we verify the data obtained from disk against that checksum." in an older post.
This allows to detect errors., but I am curious about deliberate manipulation/alteration of the backup file. I am certain they are not likely, but are they "theoretically" possible?