Nippon Telegraph and Telephone Corporation

Takayuki Miura

Provided is a retention-replacement probability generation device that is capable of generating retention-replacement probability that realizes retention-replacement perturbation of a suitable level. Included are: a global optimal solution determining unit that, outputs a global optimal solution in a case where a global optimal solution exists that is a replacement probability of the attribute values in which the transition matrix P and histogram vector expression v of the attribute values yield ∥Pv−v∥=0; a region generating unit that, in a case where the global optimal solution does not exist, generates a region that is defined by an inequality equivalent to conditions for both replacement probabilities corresponding to i'th and j'th attribute values satisfying ε-differential privacy, and an inequality equivalent to conditions for the replacement probability of one and the retention probability of the other corresponding to the i'th and the j'th attribute values satisfying ε-differential privacy.

Retention-replacement probability generation device, retention-replacement perturbation device, retention-replacement probability generation method, retention-replacement perturbation method, and program

An identification-estimation risk assessment apparatus includes a first calculation unit for calculating a first value ΣPr[Δ(t)=t'oγ], which is a sum related to all shuffles of a probability Pr[Δ(t)=t′oγ] that a table Δ(t) obtained by anonymizing the original table t through randomization Δ coincides with a table t′oγ represented as a composite of a shuffle γ and the anonymized table t′; a second calculation unit for calculating a second value ΣPr[Δ(t)=t′oγ], which is a sum related to a shuffle that satisfies γ(r)=r′ of the probability Pr[Δ(t)=t′oγ]; and a third calculation unit for calculating a third value ΣPr[Δ(t)=t′oγ]/ΣPr[Δ(t)=t′oγ] as a risk assessment value of a risk that a record number r is identified and estimated as corresponding to a record number r′, based on the first value and the second value.

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Musashino, Japan

Takayuki Miura