4 papers
Secure multiplex coding to attain the channel capacity in wiretap channels
Daisuke Kobayashi, Hirosuke Yamamoto, Tomohiro Ogawa
It is known that a message can be transmitted safely against any wiretapper via a noisy channel without a secret key if the coding rate is less than the so-called secrecy capacity…
Asymptotically Optimal Tree-based Group Key Management Schemes
Hideyuki Sakai, Hirosuke Yamamoto
In key management schemes that realize secure multicast communications encrypted by group keys on a public network, tree structures are often used to update the group keys efficien…
Optimal multiple assignments based on integer programming in secret sharing schemes with general access structures
Mitsugu Iwamoto, Hirosuke Yamamoto, Hirohisa Ogawa
It is known that for any general access structure, a secret sharing scheme (SSS) can be constructed from an (m,m)-threshold scheme by using the so-called cumulative map or from a (…
Quantum Secret Sharing Schemes and Reversibility of Quantum Operations
Tomohiro Ogawa, Akira Sasaki, Mitsugu Iwamoto +1
Quantum secret sharing schemes encrypting a quantum state into a multipartite entangled state are treated. The lower bound on the dimension of each share given by Gottesman [Phys.…