US Patent 10027486 Homomorphic encryption for database querying

This disclosure concerns homomorphic encryption for database querying. Numerical values are encrypted using keys and random numbers to produce a ciphertext. The ciphertext is homomorphic and is comprised of two or more sub-ciphertexts. Queries based on addition, average and multiplication operations can be performed without decrypting the numerical values relevant to the query. Each sub-ciphertext is stored in a single record and in separate attributes. There is disclosed methods of encrypting and decrypting, creating a suitable table, querying such a database and updating such a database.