Theme: military model does not provide enough controls for
commercial fraud, etc. because it does not cover the right aspects
of integrity
Data items: “Constrained Data Items” (CDI) to which
the model applies, “Unconstrained Data Items” (UDIs) to
which no integrity checks are applied, “Integrity Verification
Procedures” (IVP) that verify conformance to the integrity
specification when IVP is run, “Transaction Procedures”
(TP) takes system from one well-formed state to another
Clark-Wilson Certification and Enforcement Rules
C1.
All IVPs must ensure that all CDIs are in a valid state
when the IVP is run.
C2.
All TPs must be certified to be valid, and each TP is
associated with a set of CDIs it is authorized to manipulate.
E1.
The system must maintain these lists and must ensure
only those TPs manipulate those CDIs.
E2.
The system must maintain a list of User IDs, TP, and
CDIs that that TP can manipulate on behalf of that user, and must ensure
only those executions are performed.
C3.
The list of relations in E2 must be certified to meet
the separation of duty requirement.
E3.
The system must authenticate the identity of each user
attempting to execute a TP.
C4.
All TPs must be certified to write to an append-only CDI
(the log) all information necessary to reconstruct the operation.
C5.
Any TP taking a UDI as an input must be certified to
perform only valid transformations, else no transformations, for any
possible value of the UDI. The transformation should take the input from
a UDI to a CDI, or the UDI is rejected (typically, for edits as the
keyboard is a UDI).
E4.
Only the agent permitted to certify entities may change
the list of such entities associated with a TP. An agent that can
certify an entity may not have any execute rights with respect to that
entity.
