Oblivious Ram (ORAM) is a cryptographic technique that is used for secure DB querying without leakage on the access patterns. There are several schemes for ORAM, amongst the most popular ones, there is Path ORAM. However, and as far as I understand it, ORAM is tied to a client/server(s) configuration, in other words, it let a given client outsource DB services. In this, case the DB belongs to the client, and security follows from the server not learning anything from the DB content and the access pattern. My Question is as follows:
In the case the DB does not belong to the client, and the definition of security is expanded such that the server does not learn anything from the query but also the client does not learn anything from the DB, except the result of query (A third party DB), can I still use ORAM, how should I do it? and how an scheme like Path ORAM would work instead? Any insight on this precise topic is more than welcome!