Final Interpretation for RI # 85 - SOF Claims additional to the overall claim

Date: 02/11/2002
Subject: SOF Claims additional to the overall claim
CC Part #1 Reference: 
CC Part #2 Reference: 
CC Part #3 Reference: CC Part 3, Section 4.5 (APE_REQ)
CC Part 3, Section 5.6 (ASE_REQ)
CEM Reference: 

Issue:

The circumstances under which claims are made under APE_REQ.1.11C, ASE_REQ.1.10C (CEM APE/ASE_REQ.1-16) are unclear.



Interpretation

Work units APE/ASE_REQ.1-16 refer to the case where a PP or ST author wishes to set specific SOF requirements (e.g. higher than the minimum level or by using a metric). Requirements under this heading are at the discretion of the PP or ST author, but must be consistent with other parts of the PP or ST (e.g. TOE description).

Specific Changes

In CC, Part 3 the following changes are made

The requirement APE_REQ.1.11C is updated as follows:

The statement of security requirements shall identify all security functional requirements for which an explicit strength of function claim is required, together with the explicit strength of function claim for each such security functional requirement.

The requirement ASE_REQ.1.10C is updated as follows:

The statement of security requirements shall identify all security functional requirements for which an explicit strength of function claim is required, together with the explicit strength of function claim for each such security functional requirement.

In the CEM the following changes are made:

The evaluator shall check that the PP identifies any specific TOE security functional requirements for which an explicit strength of function is appropriate, together with the specific strength of function or metric as applicable.

This work unit refers to the case where a PP author requires to set specific SOF requirements (i.e. higher than the overall SOF claim of the PP) or by using a metric. A specific SOF claim for a TOE security functional requirement may be specified by a PP author. In the absence of any specific claim, the overall claim for the PP applies for all TOE security functional requirements stated in the PP. The evaluator should confirm the presence or absence of explicit SOF claims is consistent with other parts of the PP.

A PP could potentially have varying specifications of SOF claims. There can be an overall SOF claim for a PP and within a PP the TOE security functional requirements could have a SOF claim specified for it.

The evaluator shall check that the ST identifies any specific TOE security functional requirements for which an explicit strength of function is appropriate, together with the specific strength of function or metric as applicable.

This work unit refers to the case where an ST author requires to set specific SOF requirements (i.e. higher than the overall SOF claim of the ST) or by using a metric. A specific SOF claim for a TOE security functional requirement may be specified by a PP author. In the absence of any specific claim, the overall claim for the ST applies for all TOE security functional requirements stated in the ST. The evaluator should confirm the presence or absence of explicit SOF claims is consistent with other parts of the ST.

An ST could potentially have varying specifications of SOF claims. There can be an overall SOF claim for an ST and within an ST the TOE security functional requirements could have a SOF claim specified for it.

Rationale


The requirements in the CC, as expressed in Part 1 B/C.2.6 are for a claim for minimum strength of function in all cases where AVA_SOF.1 is claimed. In the case of a PP the author may not know whether TOE implementation will include a probabilistic or permutational mechanism. The inclusion of a minimum SOF claim is an assertion of a minimum standard for the TOE, expressed as a requirement, not a statement about whether probabilistic or permutational mechanisms are included in the TOE.