Cryptographic system and computer readable medium

摘要

A cryptographic system (10) performs a cryptographic process using a basis. B and a basis B*. An encryption device (200) generates a ciphertext including a transmission-side vector being a vector in the basis B and being generated using one vector of a first vector consisting of coefficients yj of a polynomial having xi as roots and a second vector consisting of v1i being a power of v1. A decryption device (300) decrypts the ciphertext generated by the encryption device (200) with a decryption key including a reception-side vector being a vector in the basis B* and being generated using the other vector of the first vector and the second vector.

主权项

1. A cryptographic system to perform a cryptographic process using a basis B and a basis B*, the cryptographic system comprising:
processing circuitry to: generate a transmission-side vector being a vector in the basis B and being generated using one vector of a first vector consisting of coefficients yj (j=1, . . . , n) of a polynomial having attribute information xi (i=1, . . . , n′, n′ being an integer from 1 to n−1, n being an integer of 2 or greater) as roots and a second vector consisting of v1i (i=0, . . . , n−1) being a power of predicate information v1; perform a pairing operation on the transmission-side vector and a reception-side vector being a vector in the basis B* and being generated using another vector of the first vector and the second vector; and generate at least one of a ciphertext, decryption key and signature output of reduced size containing the transmission-side vector or reception-side vector to reduce processing time of an encryption or decryption process.