16 ms·

The brilliant thing about all of the free space that Dropbox "gives away" is that most people who get it (90%? more?) don't actually use it. I'm up to 4.9GB of

The brilliant thing about all of the free space that Dropbox "gives away" is that most people who get it (90%? more?) don't actually use it. I'm up to 4.9GB of free space, but I'm only using 7.6%, so I'm well under 2GB. And I would venture to guess that I'musing more space than the average free user. So their cost isn't even the pretty-low cost of (cost to store 128MB * the number of people who do the task). It's the tiny cost of (cost to store 128MB * the number of people who do the task * percentage of those people that actually use the space).

mitjak 16y ago
The only reason my situation is the same as yours is because the plans are a tad too pricey for me. If I could indeed afford over 20-30GB of space, I would include all my family photos and music to be uploaded to Dropbox as well. The latter could perhaps be rectified by a (hopefully upcoming) cloud music service (with a decent music catalogue), but the photos are really a problem.
gst 16y ago
Even less space is required. Dropbox stores duplicate files only once. So if many users store the same files the cost per user is practically zero. That's also the reason why uploads are so fast. If a file is already on the server it isn't uploaded again.
- almost 16y ago
  Is it really shared between accounts? So for example if I knew someone with Dropbox had a file that could have one of several contents and I wanted to know which of those contents they had I could try uploading the different versions and see which one uploaded faster? A little far fetched maybe, but I'm sure there's a way to exploit something somewhere using that....
  - riobard 16y ago
    You can test this with relatively large files. If a 100mb file finishes syncing to Dropbox within seconds over a slow DSL, you can be pretty sure that someone has already uploaded a copy there before you do.
  - gst 16y ago
    Yes - this should work. There are even other ways how you might be able to exploit this. I don't exactly know how Dropbox verifies if your file is already on the server. But if they only check a hash of the file it might be sufficient to know the hash of any file stored on Dropbox to gain access to the full file. Of course, this is just a speculation and there might be more security precautions in place. Such as, e.g., sending the client various challenges about the hashes of particular byte ranges. In addition, also the copyright implications of this are interesting. Consider that you've shared a directory with your friends and that you upload some copyrighted movie (that is already on their servers and not really uploaded). Are you then the one liable for the damages (if sued), or is the original (first) uploader of the file liable?
  - AdamTReineke 16y ago
    Yes. I threw a 20MB e-book PDF into my Dropbox and it was instantly marked as uploaded. The only exploit would be that you could determine if a specific file was uploaded, not how many people had copies of the file or who those people were.

mitjak 16y ago

The only reason my situation is the same as yours is because the plans are a tad too pricey for me. If I could indeed afford over 20-30GB of space, I would include all my family photos and music to be uploaded to Dropbox as well. The latter could perhaps be rectified by a (hopefully upcoming) cloud music service (with a decent music catalogue), but the photos are really a problem.

gst 16y ago

Even less space is required. Dropbox stores duplicate files only once. So if many users store the same files the cost per user is practically zero. That's also the reason why uploads are so fast. If a file is already on the server it isn't uploaded again.

almost 16y ago
Is it really shared between accounts? So for example if I knew someone with Dropbox had a file that could have one of several contents and I wanted to know which of those contents they had I could try uploading the different versions and see which one uploaded faster? A little far fetched maybe, but I'm sure there's a way to exploit something somewhere using that....
- riobard 16y ago
  You can test this with relatively large files. If a 100mb file finishes syncing to Dropbox within seconds over a slow DSL, you can be pretty sure that someone has already uploaded a copy there before you do.
- gst 16y ago
  Yes - this should work. There are even other ways how you might be able to exploit this. I don't exactly know how Dropbox verifies if your file is already on the server. But if they only check a hash of the file it might be sufficient to know the hash of any file stored on Dropbox to gain access to the full file. Of course, this is just a speculation and there might be more security precautions in place. Such as, e.g., sending the client various challenges about the hashes of particular byte ranges. In addition, also the copyright implications of this are interesting. Consider that you've shared a directory with your friends and that you upload some copyrighted movie (that is already on their servers and not really uploaded). Are you then the one liable for the damages (if sued), or is the original (first) uploader of the file liable?
- AdamTReineke 16y ago
  Yes. I threw a 20MB e-book PDF into my Dropbox and it was instantly marked as uploaded. The only exploit would be that you could determine if a specific file was uploaded, not how many people had copies of the file or who those people were.