Abstract: One encryption design mechanism based on sensitive fields is mainly adopted in database encryption,which sensitive fields is correspondence to keys one by one.But if all the keys are fixed in advance,new security problemwill emerge.So how to generate and save the encryption keys is of grent importance.One derivative echanism of two-stage encryption key is adopted,including management keys and encryption keys.encryption keys which come from thetransformed results in sixty round of DES encryption algorithm on main keys areused to encrypt sensitive fields.Only a few management keys are needed to set in advance,but the encryption keys are dynamically generated by programming.What the user needs to do is to store several management keys safely,without considering the security storage and communication of theencryption keys.The way of deriving encryption keys by DES Encryption Algorithmcan meet the needs of encryption keys in database encryption,and derive 256 times encryption keys for the safety storage and management of the encryption keys.

Key words: DES encryption algorithm, double encryption-key, management key, encryption key