A multilevel encryption scheme for database security

An encryption scheme is proposed which allows a hierarchical organization of keys used to encrypt and decrypt data stored in databases. The scheme uses the same method as the RSA cryptosystem [RISH78] to encrypt and decrypt data, with additional restrictions on the availability of the encryption information to the public. Its security is based on the Discrete Logarithm problem [DIHE76] which is known to be NPI. Each user is issued a key which is used for decryption and user clearance verification.