After a file is uploaded, encrypted and distributed to the nodes, it is no longer kept on the server. Only a record of the nodes that contain its different blocks is stored, because this is necessary to rebuild the file, Malone said.
If a government agency were to seize the server and take it away, the block replication process would fail because the nodes would start going offline, which would make the file unrecoverable, Malone said. There are a few ways to recover the data, but it is very difficult and it involves seizing a large number of nodes or compromising the server while it's still online and coercing the owner to provide the passwords necessary to decrypt the files.
There is a way to provide "plausible deniability" for the owner and it involves initially seeding the server with a large number of dummy files that contain random data, but this functionality is not yet built into the system, Malone said.
The user can say that he created the system, but did not put any real data in it, even though he did also upload some real files along with the dummy ones.
Because the random data in the dummy files looks the same as the random data in encrypted files, when trying to recover a file there is no way to tell if the password supplied by the user was correct and a dummy was decrypted, or if the password was wrong, the researcher said.
In this way, the user can supply the wrong password for the files he knows are real and the other party would have no way to prove that the password was correct or incorrect.
While the legality of building such a botnet is questionable, this system could also be set up as a collaborative effort, where users volunteer their browsers themselves and are able to upload files to the system, Malone said.
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