MULTILEVEL SECURE DATABASE ENCRYPTION WITH SUBKEYS

In this paper, we propose a multilevel database encryption system with subkeys. This new system is called the record-oriented cryptosystem w hich encrypts each record with different field-subkeys according to a security class of the data element. Each field is decrypted individual ly by the field-subkeys of which security class is higher than or equa l to that of the encrypted field-subkeys. This system is based on the Chinese Remainder Theorem. Our scheme can protect the finest level of granularity such as relation level, attribute level, tuple level, or d ata element level in the relational database model.