RussellMc wrote:

>> "SpiderOak saves storage space using intensive data de-duplication.
>> In this way, SpiderOak can often keep all of the historical versions
>> of a file, using about the same amount of space that would be
>> required to store only the most recent version."
>=20
> This COULD be done at each node without such storage being 'in the
> cloud'. Would need to read more ... .

In principle, but I highly doubt it. For that, the local software would
have to be able to create a local diff, which means it needs a base line
storage of everything that's in the affected directories, basically
duplicating the local storage requirements. Or it would have to hook
into the file system, to intercept any writes -- and keep a local
storage of only those until the next sync. And this for multi-platform
client software that's free... I wouldn't bet on it :)=20


>> I'm not sure there is a service that actually stores only data that
>> has been encrypted with a key that only the user knows.
>=20
> Any system where you encrypt the data before submitting it meets
> whatever security you provide. You could one-time-pad process the
> data at each end, or use PGP or whatever, completely invisibly to
> SpiderOak or whatever other transport system. Liable to play haoc
> with web based de-duplication though :-) .=20

.... and with a number of other features of the service. It wouldn't
invalidate their versioning, but would drive up the (online) storage
requirements for this versioning, because there's no reasonable (small)
diff between encrypted versions of a file; each version is a fully new
version. It also wouldn't play well with their automatic sync features,
as it would only sync the encrypted versions -- you'd have to take care
of the syncing of the original files with the (local) encrypted files. A
two-stage sync is much easier to get out of sync, especially since it's
not likely that they provide trigger hooks in their software that allow
you to run your local sync whenever they update a file.

Local pre-encryption is in principle always possible, but it invalidates
most of the convenience features of these services -- and if you do
this, you probably can use a Gmail account just the same and get 8GB for
free.

Gerhard
--=20
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