A method and apparatus are utilized to incrementally encrypt stored information, and can be applied to an existing medium storing unencrypted information. Information can be conditionally encrypted and/or decrypted as necessary and a separate storage area can be used to record whether a given block of information is stored encrypted or unencrypted. An embodiment of the present invention can be used as a retrofit device in a mechanism to encrypt information without causing undue interruption of normal operations. A variety of mechanisms and policies can also be used to manage, set and eliminate encryption keys.