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I am missing something. The encryption key is the hash of a chunk of data, so for identical chunks the encrypted data is identical. Understand. But suppose I
by ksri 15y ago
I am missing something.
The encryption key is the hash of a chunk of data, so for identical chunks the encrypted data is identical. Understand.
But suppose I want to decrypt. To generate the key, I need to hash the unencrypted chunk of data. But if I have unencrypted data, I don't really need decryption.
I guess my question is - how does decryption work when I have lost the files on my local machine, but I remember my password?
- xtacy 15y agoGood question! [Wild thought] Create a file with a list of H(chunk) forall chunk you own. You encrypt this file with a local password that the storage provider does NOT see and plainly store it.
- ksri 15y agoI re-read the paper, and they seem to be doing what you describe. The list of H(chunk) is called "Chunk Map", and local password is called "dedicated map key"... .. but after that they get into another round of encryption with the users public key - that's where I get lost.
- bdhe 15y agoThis comes up often. I took it upon myself to write it out without too many technical details. You can see it here (in particular, the section about uploading and syncing files): http://crypto.stanford.edu/~ananthr/dropbox/ http://crypto.stanford.edu/~ananthr/dropbox/
- amalcon 15y agoThe most obvious workaround for this would be to remember the key. Each user's fileset includes a copy of the key generated from each file, encrypted with that user's private key. The user would request the files, and also the encrypted keys. They would then decrypt said files locally.