I'm not sure how this is implemented, but I can imagine a case in which this would work out. First, let's assume the data is encrypted with some strong encrypt

I'm not sure how this is implemented, but I can imagine a case in which this would work out. First, let's assume the data is encrypted with some strong encryption algorithm and similarly strong encryption key. This provides some security, but a lot less than you might think. Because data is being stored locally for a potential attacker, it is very easy for them (hypothetically) to make a large number of copies of that data and then distribute it for brute-forcing. This dramatically decreases the amount of time it would take to crack the encryption, even by brute force. [1] However, this assumes that they have the entire data at their disposal. In a torrent, you oftentimes only have chunks (say 1 MB each), and everyone doesn't download the entire torrent. So someone may only have a few megabytes worth of data. Still that's potentially enough data to contain sensitive information, even a few pictures. However, now let's assume that the data is scrambled. This means that the data is divided into 1 MB chunks of data that are not necessarily contiguous. So a 1 GB torrent would have 1000 chunks of 1 MB each, but each chunk of size 1 MB would have data from various parts of the torrent. The scrambling mechanism could be randomized and sent (securely) to the second party so that they are the only ones able to fit the pieces of data together correctly. The protocol could enforce that individuals cannot host more than _____ chunks/MB of the same file, or even that a file has to be distributed among IP addresses from different IP blocks (allocated geographically), thus reducing the chance that a single attacker has access to large parts of the same file. It does not rule out the possibility of a coordinated attack over a large geographic region, but it reduces the risk, and it would probably suffice for most use cases. Heck, people send public Dropbox links over plaintext, so it's not like we're talking about people who place a high value on security anyway (or, at least, people who think that their data is valuable enough to be worth the effort to crack). [1] There's a nice website that illustrates the advantage of having local copies of the encrypted data, but I can't find it now. It was basically a password strength-checking website that tells you how long it would take to crack your password by various methods.