Abstract: A secure database system comprises a server having a database including at least one personal information table and at least one further table containing information relating to the persons whose details are stored in the personal information table. The keys of the tables in the database are unrelated, so that it is impossible to determine solely from information in the server which record in the further table corresponds to which record in the personal information table. Thus, even if a hacker obtains access to the database, the hacker will not be able to relate information in the different tables. Each legitimate client uses an encryption process to convert a personal identifier value, which identifies the record relating to a particular person in the personal information table, into a pseudo-identifier value, which identifies a record relating to the same person in the further table.

Abstract: A secure database system comprises a server having a database including at least one personal information table and at least one further table containing information relating to the persons whose details are stored in the personal information table. The keys of the tables in the database are unrelated, so that it is impossible to determine solely from information in the server which record in the further table corresponds to which record in the personal information table. Thus, even if a hacker obtains access to the database, the hacker will not be able to relate information in the different tables. Each legitimate client uses an encryption process to convert a personal identifier value, which identifies the record relating to a particular person in the personal information table, into a pseudo-identifier value, which identifies a record relating to the same person in the further table.