| 摘要 |
PROBLEM TO BE SOLVED: To reduce both the size of encryption vector data and the time for calculating concealment distance in calculation of the concealment distance with the use of homomorphic encryption.SOLUTION: As one example of an encryption processing device, the device includes a polynomial expression conversion unit (hereinafter referred to as a), a weighting calculation unit (b), a homomorphic encryption unit (c) and a concealment distance calculation unit (d). (a) obtains a first polynomial expression from a first vector with the use of a first conversion polynomial expression, and a second polynomial expression from a second vector with the use of a second conversion polynomial expression. (b) obtains first weighting relating to concealment distance of the first vector, and second weighting relating to concealment distance of the second vector. (c) encrypts each of the first polynomial expression, the second polynomial expression, the first weighting and the second weighting with the use of a homomorphic encryption method. (d) obtains encryption concealment distance corresponding to encryption of concealment distance of the first vector and the second vector from each of those encrypted by (c). |
