5 ms·

I might have misunderstood what you meant, but #1 is invalid. If I can look at my data any time I want, I just need the key to it. Dropbox just gives me access

I might have misunderstood what you meant, but #1 is invalid. If I can look at my data any time I want, I just need the key to it. Dropbox just gives me access to the encrypted stream. Giving access to my data to someone else would therefore just be a question of sharing the key with that person, again, without Dropbox ever having access to this key. Your killer argument is to me #3. If you don't trust a company, don't do business with it. It all comes down to this.

kwis 16y ago
Tarsnap provides exactly the sort of service you're referring to, where they only store encrypted data and don't have a copy of the key. I'm a big fan of that architecture, if only because it greatly reduces the payoff of a successful attack. When everything is stored unencrypted (or with a common master key), there's an absolutely massive payoff for the hacker who breaches the security.
- shin_lao 16y ago
  Tarsnap is great and its author knows what he's doing but dropbox is many UA ahead in terms of useability and platform interoperability. Dropbox is incredibly easy to use, that's where its power comes from. It's "secure enough" for casual use. Additionally I believe you can't share data between users with tarsnap. There is a market opportunity for a corporate-level secure data exchange infrastructure.
  - randombit 16y ago
    Tahoe-LAFS provides a storage service that is encrypted by the client, but the original uploader of the data is still able to delegate read-only or read-write access to others on a per-file or per-directory basis. The overall design, including how it is possible to do secure delegation, is fairly well described in a paper from the 'Storage Security and Survivability 2008' workshop - http://tahoe-lafs.org/~zooko/lafs.pdf http://tahoe-lafs.org/~zooko/lafs.pdf
  - w1ntermute 16y ago
    > dropbox is many UA ahead in terms of useability and platform interoperability That's besides the point. Tarsnap is more than useable enough for its target audience, which is why cperciva (rightfully) doesn't give a rat's ass about making it as user-friendly as Dropbox and its ilk. The two issues are completely separate. Implementation of client-side encryption and user-friendliness are not mutually exclusive. Tarsnap is simply proof that client-side encryption is entirely within the realm of possibility for cloud-based data storage services.
    - fluidcruft 16y ago
      Dropbox+ecryptfs is pretty usable, too.
palish 16y ago
One of the reasons Dropbox is successful is because anyone can use it. Even your mother. In fact, one of the reasons Drew was originally accepted into the YC program was because his sister was using it when he applied. "If I can look at my data any time I want, I just need the key to it. Dropbox just gives me access to the encrypted stream." In order for the data to be encrypted securely, you would need to generate a key on your own computer which Dropbox then uses to perform the encryption. (Tarsnap works this way.) Forcing Drew's sister (or your mother) to generate a key would be bad for accessibility.
- shin_lao 16y ago
  The authentication token can be generated and managed by the software. It would then be protected by the account password, if any (Windows and MacOS X offer this feature). Doable, and even better, you can make that a 30 € / month corporate option. ;)
  - palish 16y ago
    If the key file is stored on Dropbox servers, then Dropbox has access to all of your files. This defeats the original purpose (security). If the key file is not stored on Dropbox servers, then you can't easily use Dropbox across several different computers. This defeats the other purpose (accessibility).
    - shin_lao 16y ago
      You can store a key escrow on the dropbox server protected by a password or a token. Just a matter of designing something secure and useable. Not easy, but possible.
      - piaskal 16y ago
        When you forget your password you'll lose access to all of your data. Password recovery won't be possible if the key is password protected.
Groxx 16y ago
Have fun decrypting AES in Javascript, and downloading the file through your browser. (edit: on your cell phone...)
- tlrobinson 16y ago
  Hint: downloading client-side generated files is not possible without assistance from Flash.
  - mnutt 16y ago
    Downloading client-side generated files is possible using data-uri. However these are usually small; it would be very difficult to store a 1GB file in memory (in javascript) while you decrypted it and I doubt data-uris that large work across different browsers.
    - tlrobinson 16y ago
      True, but there's no way to specify the filename and extension, so in practice you have to use Flash.
      - mnutt 16y ago
        It depends on the browser. Safari 5 works, but Chrome doesn't, not sure about Firefox, and I suspect IE doesn't. I use it on my torrent-conversion bookmarklet on http://hid.im http://hid.im.
  - njs12345 16y ago
    Not quite true: http://jszip.stuartk.co.uk/ http://jszip.stuartk.co.uk/
- jlouis 16y ago
  My Cellphone is as powerful as a 2002 state-of-the-art desktop machine. There are problems here, but this is not it.

kwis 16y ago

Tarsnap provides exactly the sort of service you're referring to, where they only store encrypted data and don't have a copy of the key. I'm a big fan of that architecture, if only because it greatly reduces the payoff of a successful attack. When everything is stored unencrypted (or with a common master key), there's an absolutely massive payoff for the hacker who breaches the security.

shin_lao 16y ago
Tarsnap is great and its author knows what he's doing but dropbox is many UA ahead in terms of useability and platform interoperability. Dropbox is incredibly easy to use, that's where its power comes from. It's "secure enough" for casual use. Additionally I believe you can't share data between users with tarsnap. There is a market opportunity for a corporate-level secure data exchange infrastructure.
- randombit 16y ago
  Tahoe-LAFS provides a storage service that is encrypted by the client, but the original uploader of the data is still able to delegate read-only or read-write access to others on a per-file or per-directory basis. The overall design, including how it is possible to do secure delegation, is fairly well described in a paper from the 'Storage Security and Survivability 2008' workshop - http://tahoe-lafs.org/~zooko/lafs.pdf http://tahoe-lafs.org/~zooko/lafs.pdf
- w1ntermute 16y ago
  > dropbox is many UA ahead in terms of useability and platform interoperability That's besides the point. Tarsnap is more than useable enough for its target audience, which is why cperciva (rightfully) doesn't give a rat's ass about making it as user-friendly as Dropbox and its ilk. The two issues are completely separate. Implementation of client-side encryption and user-friendliness are not mutually exclusive. Tarsnap is simply proof that client-side encryption is entirely within the realm of possibility for cloud-based data storage services.
  - fluidcruft 16y ago
    Dropbox+ecryptfs is pretty usable, too.

palish 16y ago

One of the reasons Dropbox is successful is because anyone can use it. Even your mother. In fact, one of the reasons Drew was originally accepted into the YC program was because his sister was using it when he applied. "If I can look at my data any time I want, I just need the key to it. Dropbox just gives me access to the encrypted stream." In order for the data to be encrypted securely, you would need to generate a key on your own computer which Dropbox then uses to perform the encryption. (Tarsnap works this way.) Forcing Drew's sister (or your mother) to generate a key would be bad for accessibility.

shin_lao 16y ago
The authentication token can be generated and managed by the software. It would then be protected by the account password, if any (Windows and MacOS X offer this feature). Doable, and even better, you can make that a 30 € / month corporate option. ;)
- palish 16y ago
  If the key file is stored on Dropbox servers, then Dropbox has access to all of your files. This defeats the original purpose (security). If the key file is not stored on Dropbox servers, then you can't easily use Dropbox across several different computers. This defeats the other purpose (accessibility).
  - shin_lao 16y ago
    You can store a key escrow on the dropbox server protected by a password or a token. Just a matter of designing something secure and useable. Not easy, but possible.
    - piaskal 16y ago
      When you forget your password you'll lose access to all of your data. Password recovery won't be possible if the key is password protected.

Groxx 16y ago

Have fun decrypting AES in Javascript, and downloading the file through your browser. (edit: on your cell phone...)

tlrobinson 16y ago
Hint: downloading client-side generated files is not possible without assistance from Flash.
- mnutt 16y ago
  Downloading client-side generated files is possible using data-uri. However these are usually small; it would be very difficult to store a 1GB file in memory (in javascript) while you decrypted it and I doubt data-uris that large work across different browsers.
  - tlrobinson 16y ago
    True, but there's no way to specify the filename and extension, so in practice you have to use Flash.
    - mnutt 16y ago
      It depends on the browser. Safari 5 works, but Chrome doesn't, not sure about Firefox, and I suspect IE doesn't. I use it on my torrent-conversion bookmarklet on http://hid.im http://hid.im.
- njs12345 16y ago
  Not quite true: http://jszip.stuartk.co.uk/ http://jszip.stuartk.co.uk/
jlouis 16y ago
My Cellphone is as powerful as a 2002 state-of-the-art desktop machine. There are problems here, but this is not it.