Integrity controls for military and commercial applications

Because it is generally not possible to prevent the destruction or alteration of data when objects are stored or transmitted outside the security perimeter of a TCB (trusted computer base), the emphasis is placed on detecting any illicit data, including the results of computer viruses and Trojan Horse programs, using cryptographic checksums and digital signature techniques. It is concluded that a mandatory integrity policy consisting of the Biba hierarchical integrity policy extended to include integrity categories and multilevel integrity-trusted subjects, plus a discretionary integrity policy that uses a digital signature mechanism incorporated in a file label to indicate who created or produced that file, can provide integrity controls very well-suited to the networking environment