Abstract
In Crypto2000, the concept of quantum public key cryptosystems and its concrete scheme OTU2000 were first proposed. We actually implemented the key generation, encryption and decryption for the rational number field and imaginary quadratic fields, and then performed numerical experiments about key generation. For actual key generation, it was necessary to consider the choice and the order of parameters. Taking this into account, we propose a concrete algorithm of key generation. Intending to increase the density of the generated knapsack problem, we also propose a slightly extended scheme of OTU2000.
