On 23 May 2018 at 07:52, David Fetter <da...@fetter.org> wrote: > On Tue, May 22, 2018 at 08:34:18AM +0200, Tal Glozman wrote: > > Hello PostgreSQL Team, > > > > I'm doing a project at my university (HU Berlin) involving > > homomorphic encrypted searches on data bases. Does PostgreSQL > > support homomorphic encryption-based searches? > > Yes, in the sense that PostgreSQL has Turing-complete languages for > expressional indexes, so to the extent that Turing machines can solve > the problem you want solved, the capability is there. > > What would a system that supported homomorphic encrypted searches look > like from an operational point of view? >
Presumably it'd have to support some non-equality ops like < and > for b-tree indexing, so you can compare two encrypted texts without decryption. If the user can supply cleartext to be compared against, this exposes search-based plaintext attacks where you can discover the plaintext over time with iterative searches over modified plaintext. My understanding of homomorphic encryption is that it's generally more useful for data-modifying operations. For example, you might want to add a value to a balance without being able to read the balance and learn the current value. I haven't heard of it being used for searches before. -- Craig Ringer http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services