Method and system for searching encrypted data

A method, implemented on a machine having at least one processor, storage, and a communication platform connected to a network for searching encrypted data, the method comprising:

• receiving an encrypted query for encrypted documents;
• determining, based on the encrypted query, one or more index locations in a first encrypted index and a second encrypted index, wherein the first encrypted index maps encrypted keywords to full blocks each of which has a same size and is fully filled with encrypted document IDs, and the second encrypted index maps encrypted keywords to partial blocks each of which has the same size and is partially filled with encrypted document IDs, and wherein the first encrypted index is built based on an append-only encrypted hash table and the second encrypted index is built based on an encrypted oblivious RAM;
• identifying one or more encrypted document IDs from the one or more index locations;
• and
• providing the one or more encrypted document IDs as a response to the encrypted query.

A machine-readable tangible and non-transitory medium having information for searching encrypted data, wherein the information, when read by the machine, causes the machine to perform the following:

• receiving a search request for encrypted documents at a client device;
• generating an encrypted query based on the search request;
• sending the encrypted query to a server that stores a first encrypted index and a second encrypted index, wherein the first encrypted index maps encrypted keywords to full blocks each of which has a same size and is fully filled with encrypted document IDs, and the second encrypted index maps encrypted keywords to partial blocks each of which has the same size and is partially filled with encrypted document IDs;
• receiving one or more encrypted document IDs from the server, determined based on the encrypted query being searched against both the first encrypted index and the second encrypted index;
• searching against a non-encrypted index based on the search request to determine one or more non-encrypted document IDs, wherein the non-encrypted index is stored locally at the client device;
• generating a search result based on the one or more encrypted document IDs and the one or more non-encrypted document IDs;
• and
• providing the search result in response to the search request.

A machine-readable tangible and non-transitory medium having information for searching encrypted data, wherein the information, when read by the machine, causes the machine to perform the following:

• receiving an encrypted query for encrypted documents;
• determining, based on the encrypted query, one or more index locations in a first encrypted index and a second encrypted index, wherein the first encrypted index maps encrypted keywords to full blocks each of which has a same size and is fully filled with encrypted document IDs, and the second encrypted index maps encrypted keywords to partial blocks each of which has the same size and is partially filled with encrypted document IDs, and wherein the first encrypted index is built based on an append-only encrypted hash table and the second encrypted index is built based on an encrypted oblivious RAM;
• identifying one or more encrypted document IDs from the one or more index locations;
• and
• providing the one or more encrypted document IDs as a response to the encrypted query.