One embodiment of the present invention provides a system for managing keys. During operation, the system receives a request from a user at a database to encrypt/decrypt data at the database. In response to this request, the system sends a user-token to the user, wherein the user-token includes a user-key encrypted with a user-secret thereby enabling the user to decrypt the user-key with the user-secret. Next, the system receives the decrypted user-key from the user. The system then uses the user-key to encrypt/decrypt the data at the database. Finally, the system deletes the user-key at the database.