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Thread: Infinite Storage? It does exists...

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    Infinite Storage? It does exists...

    So back in November 2012, I found this start-up which claims to offer infinite space because they use encryption based on the file itself which allows deduplication if more than one user has the same file.

    The start-up is called Bitcasa and the way it works is by splitting the files in 512kb blocks and encrypting them, then uploading it to their servers. Apparently, if a user has the same blocks of other users, the blocks gets deduplicated, saving space at their end.

    What I like of this service is that they do the process invisible for the user and it integrated you account as a removable disk in which you can create folders and "copy" files as if it was an ordinary drive.

    What do you think of the service and their deduplication?

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    AFAIR, most of cloud storage providers use such techniques (I think more sophisticated than such blindly static block-boundaries). Because, if you think several petabytes-worth data, deduplication and compression are the only way to manage such huge amount of data. Considering cloud storage providers offer free accounts for some limits, this makes sense. As to inifinite storage, it's clearly marketing gimmick. Think about pigeonhole principle.
    BIT Archiver homepage: www.osmanturan.com

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    Quote Originally Posted by moisesmcardona View Post
    The start-up is called Bitcasa and the way it works is by splitting the files in 512kb blocks and encrypting them, then uploading it to their servers. Apparently, if a user has the same blocks of other users, the blocks gets deduplicated, saving space at their end.
    Hmmm... Definitely not encrypting the data. At least not in a way that is useful for the end-user. If they can detect duplication, then they have the unencrypted copy available on their end.

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    Quote Originally Posted by seth View Post
    Hmmm... Definitely not encrypting the data. At least not in a way that is useful for the end-user. If they can detect duplication, then they have the unencrypted copy available on their end.
    That must refer to the cryptographic hash.

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    Yes, they are encrypting at the client-side already, no, they can't see the data UNLESS they have the data themselves:

    http://www.extremetech.com/computing...orage-possible
    In convergent encryption, the file being encrypted is used to derive the key. So the two individuals above would encrypt their data, and as long as the files are identical, the resulting encrypted files would be identical. When those bits of data hit the Bitcasa cloud servers, it?s a trivial process to find matching files and remove the duplicates. Since Bitcasa doesn?t have the original file, they don?t have the key
    I am... Black_Fox... my discontinued benchmark
    "No one involved in computers would ever say that a certain amount of memory is enough for all time? I keep bumping into that silly quotation attributed to me that says 640K of memory is enough. There's never a citation; the quotation just floats like a rumor, repeated again and again." -- Bill Gates

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    That's interesting. Thanks for the link. I think that is likely to be more of a marketing gimmick, given the quote on their site (https://www.bitcasa.com/legal) under security:

    Your files are sent between Bitcasa?s mobile apps and our servers over a secure channel using 256-bit SSL encryption where supported. Not all mobile media players support encrypted streaming, so media files streamed from our servers are not always encrypted.
    This seems rather questionable. If they don't have access to the unencrypted data (because of how the implement the convergent encryption), then it doesn't seem like they could be streaming unencrypted media files. Perhaps the user key gets sent to the server when unencrypted streaming is needed. But in that case this would mostly be a deterrent to casual snooping of files rather than protection against a determined attack.

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    In other words, it is not secure against a known plaintext attack, but it does not matter because the key is not reused. You hash the file an use the hash as the encryption key. You keep the key secret and send them the encrypted file.

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