Comment by mapgrep | Hacker News Reader

Comment by mapgrep | Hacker News Reader

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If Dropbox were designed to handle sequentially-numbered blobs of encrypted data, changing one file would require your other devices to download only that file (an encrypted blob of roughly the same size).

With a TrueCrypt volume or other encrypted file solution on top of Dropbox, you have to resync the entire multi-GB volume any time a single file in there changes, since to Dropbox it's just one big file. (Another option is to use something like an OS X sparsebundle -- encrypted data banded across many files -- but God help you if you have two computers reading/writing from that sparsebundle at once.)

I've started using SpiderOak and it is quite efficient even though the data is encrypted such that the server admins couldn't see your data even if they wanted too. https://spideroak.com/engineering_matters SpiderOak also offers two-factor auth. (The SpiderOak UI, however, is fairly atrocious.)

If Dropbox were designed to handle sequentially-numbered blobs of encrypted data, changing one file would require your other devices to download only that file (an encrypted blob of roughly the same size).

But they do: store files and name them sequentially ;)

I think Encfs is the best solution, since it encrypts each file separately. Just mount the encrypted end over the Dropbox directory and the plaintext end somewhere else, and use it transparently.

Only part of a truecrypt volume changes when you make a change to the data within. Since Dropbox intelligently syncs files in parts, only part of a truecrypt volume has to be re-uploaded when something changes -- not the entire multi-GB file. I know because I do exactly this with a 1GB file. It takes about 2 minutes to sync when I unmount the file. Dropbox is not re-uploading all 1GB.

However, like the other commenter, I still recommend encfs for most uses.

Very interesting, I did not know that.

If you only have Macs, using an encrypted sparse bundle disk image is pretty simple, and changed files result in a small delta for dropbox to sync. It's built in and you'll be up and running in a couple minutes: http://matthew.mceachen.us/blog/free-easy-encrypted-storage-...

it is only simple if you always manage not to open such a sparse bundle on another Mac before it has been fully synced after being used on another Mac. Otherwise, you will mess up your sparse bundle sooner or later.

A service for syncing and sharing with built-in encryption might therefore me more convenient for most users. Spideroak and Wuala are two examples.

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