Patent ID: 7748041

Claim:
A system security design/evaluation support tool implemented by a computer including a storage device, deriving an assurance level of security for each of components of a subject system operating on an information processing apparatus and made up of two or more components, comprising: a threat-to-component correspondence table stored in the storage device storing therein correspondence between a threat that the subject system assumes and a security function that the component has; a risk-value table stored in the storage device storing therein information of a risk value indicative of the magnitude of a risk of the threat; a component contribution rate table stored in the storage device storing therein information on the magnitude of effect of the security function that the component has and that counters the threat; a risk-to-assurance level correspondence table stored in the storage device storing therein correspondence between a risk value and an assurance level required corresponding to the risk value; a table link use unit identifying linkages between the threat-to-component correspondence table, the risk-value table, the component contribution rate table, and the risk-to-assurance level correspondence table, based on their respective overlapping items; and a component assurance level deriving unit weighting an assurance level of each of the components, that conforms to a risk value of a threat that a security function of each of the components counters, by weighting the risk value of the threat with a component contribution rate based on linkages of the tables.