Transparent Data Encryption (TDE)

Oracle 10gR2 provides Transparent Data Encryption (TDE), encryption that is transparent for the user.

When encrypting a column, Oracle creates an encryption key for the parent table and encrypts text data in the column with a user-specified encryption algorithm. The table key is encrypted using a master key and placed in the data dictionary. The master key is stored in a secure location called a wallet, which can be a file on the database server. When a user enters data into an encrypted column, Oracle retrieves the master key from the wallet, decrypts the table key from the data dictionary, and uses it to encrypt the new data.