Dropship — successor to torrents?
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Dropship — successor to torrents?
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Re: Dropship — successor to torrents?
#2From "How does it work?" in the Readme:
Dropbox its deduplication scheme works by breaking files into blocks.
Each of these blocks is hashed with the SHA256__
algorithm and represented by the digest. Only blocks that are not yet
known are uploaded to the server when syncing.
By using the same API as the native client, Dropship pretends to sync a
file to the dropbox folder without actually having the contents. This bluff
succeeds because the only proof needed server-side is the hash of each 4MB block
of the file, which is known. The server then adds the file metadata to the folder,
which is, as usual, propagated to all clients. These will then start downloading
the file.
Re: Dropship — successor to torrents?
#3This isn't even remotely similar to bittorrent, it's more akin to rapidshare et al. You're completely at the whim of a 3rd party, Dropbox. And I'm pretty sure something like this would violate whatever contract you agree to when signing up.
So no, not a successor to torrents.
Re: Dropship — successor to torrents?
#4From "How does it work?" in the Readme: Dropbox its deduplication scheme works by breaking files into blocks. Each of these blocks is hashed with the SHA256__ algorithm and represented by the digest. Only blocks that are not yet known are uploaded to the server when syncing. By using the same API as the native client, Dropship pretends to sync a file to the dropbox folder without actually having the contents. This bl…
I still don't get it. Anyone willing to explain?
Re: Dropship — successor to torrents?
#5From "How does it work?" in the Readme: Dropbox its deduplication scheme works by breaking files into blocks. Each of these blocks is hashed with the SHA256__ algorithm and represented by the digest. Only blocks that are not yet known are uploaded to the server when syncing. By using the same API as the native client, Dropship pretends to sync a file to the dropbox folder without actually having the contents. This bl…
I still don't get it. Anyone willing to explain?
Somewhere on a Dropbox server is a file that you want. Normally the file's owner would have to share that file with you in order for it to appear in your Dropbox. But if you know the hash of file you can trick Dropbox into thinking you already have the file and are just adding it to your Dropbox. Apparently Dropbox notices they already have that file, and instead of you uploading it they just make it appear in your account. Then you can download it.
I wasn't impressed by the OP, but this is actually a really cool hack.
Re: Dropship — successor to torrents?
#6From the README, in case it wasn't obvious:
"These utilities make use of the deduplication scheme of Dropbox__ to allow for "teleporting" files into your Dropbox account given only a list of hashes, provided of course that the files already exist on their servers. This enables arbitrary, anonymous transfers of files between Dropbox accounts."
Between this and the minor information leakage issue I suspect Dropbox will be making changes to their deduplication scheme.
A simple way to fix both of these issues is to require each user to upload the complete file once, regardless of whether Dropbox already has it stored. Deduplication in storage and per-user uploading is still possible.
Also interesting to note is the Github repo for this has been deleted. Tarball of the source is still available.
Re: Dropship — successor to torrents?
#7From "How does it work?" in the Readme: Dropbox its deduplication scheme works by breaking files into blocks. Each of these blocks is hashed with the SHA256__ algorithm and represented by the digest. Only blocks that are not yet known are uploaded to the server when syncing. By using the same API as the native client, Dropship pretends to sync a file to the dropbox folder without actually having the contents. This bl…
I still don't get it. Anyone willing to explain?
Dropbox avoids having to store multiple copies of huge files by detecting duplicated files, storing only one copy, and letting every user that stores the file download from that one copy. Dropship exploits this system for filesharing by lying to the Dropbox servers and saying that it already owns a copy of the file.
For example, Person A wants to distribute a copy of a CD or something. They upload the file to Dropbox normally. They then use Dropship to create something describing that file, which they then publish. Persons B and C download that descriptor and feed it to Dropship, which tricks Dropbox into thinking that they also own copies of the file. Dropbox then lets Person B and Person C download the file that Person A wanted to distribute, and mission accomplished.
It's all very clever. I like it.
Re: Dropship — successor to torrents?
#8This isn't even remotely similar to bittorrent, it's more akin to rapidshare et al. You're completely at the whim of a 3rd party, Dropbox. And I'm pretty sure something like this would violate whatever contract you agree to when signing up. So no, not a successor to torrents.
Agreed. It's still a really neat hack, though.
Re: Dropship — successor to torrents?
#9From the README, in case it wasn't obvious: "These utilities make use of the deduplication scheme of Dropbox__ to allow for "teleporting" files into your Dropbox account given only a list of hashes, provided of course that the files already exist on their servers. This enables arbitrary, anonymous transfers of files between Dropbox accounts." Between this and the minor information leakage issue I suspect Dropbox will…
Napkin-cryptographic way how Dropbox could fix this while still getting full deduplication: currently, when the client discovers that a file has been added locally, it sends hashes of 4MB blocks, and the server considers the file added.
Additional measure at that point: the server could challenge the client to provide the values of bytes at a couple of arbitrarily chosen byte offsets of the original file. (Could precompute that, provided the queries don't repeat often).
Re: Dropship — successor to torrents?
#10This isn't even remotely similar to bittorrent, it's more akin to rapidshare et al. You're completely at the whim of a 3rd party, Dropbox. And I'm pretty sure something like this would violate whatever contract you agree to when signing up. So no, not a successor to torrents.
I'm pretty sure I've seen stuff suggesting that Dropbox occasionally purges copyrighted files from its system (which is made super-easy by the hash fingerprinting system that it uses to deduplicate storage) so I agree that this is not likely to meet most people's use case for torrents; i.e. stealing copyrighted music and films.
I wonder why the github repo has been taken down.