Filtering encrypted data using indexes

An apparatus for storing encrypted data, in a system comprising:

• a processor;
• memory in electronic communication with the processor;
• and
• instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:
• store a first ciphertext associated with a first plaintext in a data field of a database;
• store a second ciphertext associated with a second plaintext in the data field, wherein the first plaintext and the second plaintext are different;
• generate a first index for the first plaintext and a second index for the second plaintext using an indexing function, wherein an index value of the first index and an index value of the second index are the same;
• receive a query request message including a request to filter on the first plaintext for the data field;
• determine a set of index values associated with the first plaintext using the indexing function, wherein the set of index values comprises the index value of the first index and the second index, wherein determining the set of index values is based at least in part on the query request message and wherein the indexing function implements collisions to generate the same index value for the first index and the index value for the second index using the first plaintext and the second plaintext different from the first plaintext;
• and
• identify, for a set of ciphertexts stored in the data field, all indexes with index values included in the determined set of index values.

A non-transitory computer readable medium storing code for storing encrypted data, the code comprising instructions executable by a processor to:

• store a first ciphertext associated with a first plaintext in a data field of a database;
• store a second ciphertext associated with a second plaintext in the data field, wherein the first plaintext and the second plaintext are different;
• generate a first index for the first plaintext and a second index for the second plaintext using an indexing function, wherein an index value of the first index and an index value of the second index are the same;
• receive a query request message including a request to filter on the first plaintext for the data field;
• determine a set of index values associated with the first plaintext using the indexing function, wherein the set of index values comprises the index value of the first index and the second index, wherein determining the set of index values is based at least in part on the query request message and wherein the indexing function implements collisions to generate the same index value for the first index and the index value for the second index using the first plaintext and the second plaintext different from the first plaintext;
• and
• identify, for a set of ciphertexts stored in the data field, all indexes with index values included in the determined set of index values.