Finally Bitcasa CEO Explains How The Encryption Works
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Finally Bitcasa CEO Explains How The Encryption Works
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Re: Finally Bitcasa CEO Explains How The Encryption Works
#2Curious to hear if anyone has experience with this "convergent encryption."
Re: Finally Bitcasa CEO Explains How The Encryption Works
#3"HP: What do you do in terms of encryption or security?
TG: We encrypt everything on the client side. We use AES-256 hash, SHA-256 hashing for all the data.
HP: So it’s encrypted all on the client side and you can’t look at it on the server side?
TG: Exactly"
Finally, a company that gets it. I've been asking for this for a while now. I wish Dropbox and all the others would do this, too. I get it that some of Dropbox' customers may not want to deal with the encryption on the client side, but they should at least offer the option to everyone, and it should be right there every time someone wants to upload something. It would be best if it was the default option, too.
This way they won't get into the mess they got into last time with the feds asking for user data, and the clients who want full security of their data won't have to be worried about it anymore.
Re: Finally Bitcasa CEO Explains How The Encryption Works
#4This thread has a lot of discussion related to "convergent encryption."
http://news.ycombinator.com/item?id=2570538
EDIT: http://news.ycombinator.com/item?id=2461713 as well
EDIT2: Actually, there's more to this problem than just convergent encryption. If the storage provider knows which encrypted blobs belong to you, it can encrypt _some_ file and still figure out which users have copies of it. So, the storage provider, which stores a collection of encrypted blobs, should not know the blob -> list(users) association. I don't know if Bitcasa addresses this part.
Re: Finally Bitcasa CEO Explains How The Encryption Works
#5basically the argument is that this is an encryption algorithm that is deterministic as there is no randomness, after the initial value. This sounds more like a Random Oracle, http://en.wikipedia.org/wiki/Random_oracle. which by the way don't exist
Re: Finally Bitcasa CEO Explains How The Encryption Works
#6Encryption provides confidentiality in a secure system. Convergent encryption doesn't fit that bill.
Re: Finally Bitcasa CEO Explains How The Encryption Works
#7Something is twitching in the back of my mind about this. Sure, they can't look at the data based solely on the encrypted copy, but if they have a plaintext copy of a document of interest, they are able to determine which of their customers has that document, right?
Doesn't that diminish some of the privacy claims?
Re: Finally Bitcasa CEO Explains How The Encryption Works
#8"HP: What do you do in terms of encryption or security? TG: We encrypt everything on the client side. We use AES-256 hash, SHA-256 hashing for all the data. HP: So it’s encrypted all on the client side and you can’t look at it on the server side? TG: Exactly" Finally, a company that gets it. I've been asking for this for a while now. I wish Dropbox and all the others would do this, too. I get it that some of Dropbox'…
Wuala has been doing this since they started in 2007 or 2008.
Re: Finally Bitcasa CEO Explains How The Encryption Works
#9Curious to hear if anyone has experience with this "convergent encryption."
Microsoft did something here: http://research.microsoft.com/en-us/projects/farsite/
Re: Finally Bitcasa CEO Explains How The Encryption Works
#10Academic paper on convergent encryption:
http://www.ssrc.ucsc.edu/Papers/storer-storagess08.pdf
TL;DR version: take a chunk of data, encrypt it with its own sha1 hash as the key. Now you have an encrypted version that you can dedup. You can only decrypt if you already know the hash. Info about who owns any particular chunk is not kept on the server, so even if you break in to the server, all you can tell is which chunks correspond to data you already possess. Seems plausible.