Deduplication and incremental backups are table-stakes for backup software.
The reason a business would use Tarsnap rather than some other backup service is the level of confidence that Colin can provide that Tarsnap will reliably protect their data from attackers, including compelled insiders at Tarsnap.
In other words, Tarsnap can offer an enterprise an offsite backup service that is demonstrably as safe as backup data that the enterprise retains direct custody of.
That is not an offering other backup providers can reliably duplicate.
I assume you refer to all the seemingly nitty problems with the pipeline above (from what I can see, there is no way to verify that the archive wasn't tampered with).
Would you say the same about a solution that signs and encrypts the archive with gpg (signs with a machine's key and encrypts it to the owner's key). If so, can you elaborate on some examples of security problems that solution could have?
Deduplication and incremental backups are table-stakes for backup software.
The reason a business would use Tarsnap rather than some other backup service is the level of confidence that Colin can provide that Tarsnap will reliably protect their data from attackers, including compelled insiders at Tarsnap.
In other words, Tarsnap can offer an enterprise an offsite backup service that is demonstrably as safe as backup data that the enterprise retains direct custody of.
That is not an offering other backup providers can reliably duplicate.