Comment by blintz
3 years ago
Yes, every item needs to be the same size. We batch the articles into 100KB chunks, and we split articles larger than this into multiple chunks.
3 years ago
Yes, every item needs to be the same size. We batch the articles into 100KB chunks, and we split articles larger than this into multiple chunks.
Wouldn't you then have to send out multiple ciphertexts (for articles >100 KB)? Which would leak something about the size of the article...
You would. It’s important for the client to pace it’s requests in a way that does not reveal too much (for example, the client should not just request both chunks of the article at the same time). The best thing to do would probably be to have a ‘load more’ button at the bottom of a very long article that makes a separate request.
If you think about it, the pacing of user queries could always reveal something (if there’s a long gap between quarries, perhaps it’s a dense mathematics article?). So the best we can hope for is pacing requests either randomly, or for even further protection, perhaps making dummy requests on a fixed cadence.