GENERATING DEVICE, RE-ENCRYPTING DEVICE, METHOD, AND COMPUTER PROGRAM PRODUCT

摘要

According to an embodiment, a generating device includes a first key generator, a second key generator, an output unit, and an update unit. The first key generator is configured to generate a first key that is a sequence of bits according to a first key rule on the basis of a random number. The second key generator is configured to generate multiple second keys that are sequences of bits partially having correlation with one another according to a second key rule on the basis of the first key. The output unit is configured to output the first key and at least one of the second keys. The update unit is configured to generate update information for updating a second key by updating a partial sequence of the second key, the partial sequence having no correlation with the other second keys not to be updated.

主权项

1. A generating device comprising:
a first key generator configured to generate a first key that is a sequence of bits according to a first key rule for generating the first key on the basis of a random number; a second key generator configured to generate multiple second keys that are sequences of bits partially having correlation with one another according to a second key rule for generating the second keys on the basis of the first key; an output unit configured to output the first key and at least one of the second keys; and an update unit configured to generate update information for updating any one of the second keys by updating a partial sequence of the any one of the second keys, the partial sequence having no correlation with the other second keys not to be updated.