A method is disclosed for mixed enclave operation of a computer network with users employing a multi-level network security interface and users without any network security interface. Either the network security user selects or the network security interface automatically selects whether communications are permissible with other unsecured users. Where a mixed enclave operation is selected, the network security user identifies when communications are being undertaken with another secured user or a non-secured user. Communications with a non-secured user at a lower security level entail securing the data residing with the secured user from transmission back to the non-secured user.