A Database Encryption Scheme Which Allows the Computation of Statistics Using Encrypted Data

Davida, Wells and Kam used the Chinese Remainder Theorem to construct an encryption system allowing access to individual data fields of a record in a relational database. Their system is public-key in the sense that the read and write keys of a given data field are different. In this paper we present a database encryption system based on ideas similar to theirs. It is not public key, but has some other useful features. It makes possible the computation of averages and other statistics pertinent to unencrypted data, but it uses only encrypted data in the computation.