A method for encryption of the content in a database the database having database items arranged in rows and columns and being operated through a database management system, the method comprising the following steps executed by a security system connected to the database management system: defining a length of a time period to be used by the encryption method; associating each encryption key with a life time value indicating the number of time periods during which the key will be valid; for each time period generating at least one encryption key to be used when entering new database items to the database, the at least one encryption key for a particular row or column being different to the encryption key for the other rows or columns; encrypting the database items in the database in an initial time period using an encryption key generated for the initial time period; storing information about the encryption key used in the database in association with the item, said information including a timestamp indicating the time period when said item was last updated; after entering a new time period subsequent to said initial time period, scanning the database to discover items with no longer valid encryption keys, said invalid keys discovered from the encryption key life time value and the timestamp associated with the item, the timestamp indicating that the life time value has expired for the invalid keys; replacing the invalid keys discovered in the step of scanning with the encryption keys for the row or column assigned to the new time period; re-encrypting the database items that were discovered as having invalid encryption keys using the encryption keys assigned to the new time period; and updating the information including the timestamp for the encryption keys that are used to re-encrypt database items in the new time period. defining a length of a time period to be used by the encryption method; associating each encryption key with a life time value indicating the number of time periods during which the key will be valid; for each time period generating at least one encryption key to be used when entering new database items to the database, the at least one encryption key for a particular row or column being different to the encryption key for the other rows or columns; encrypting the database items in the database in an initial time period using an encryption key generated for the initial time period; storing information about the encryption key used in the database in association with the item, said information including a timestamp indicating the time period when said item was last updated; after entering a new time period subsequent to said initial time period, scanning the database to discover items with no longer valid encryption keys, said invalid keys discovered from the encryption key life time value and the timestamp associated with the item, the timestamp indicating that the life time value has expired for the invalid keys; replacing the invalid keys discovered in the step of scanning with the encryption keys for the row or column assigned to the new time period; re-encrypting the database items that were discovered as having invalid encryption keys using the encryption keys assigned to the new time period; and updating the information including the timestamp for the encryption keys that are used to re-encrypt database items in the new time period.