著者

辻井 重男 山口 浩 只木 孝太郎 五太子 政史 藤田 亮

雑誌

研究報告コンピュータセキュリティ(CSEC)

巻号頁・発行日

vol.2013, no.42, pp.1-8, 2013-07-11

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受信暗号文の各部分 (各章) を,受信側組織の代表者・管理者が,総合的・適応的で,非定常的・臨機応変的な判断により,それぞれ適切な担当者達に暗号化状態のまま配信し得るような組織間機密通信方式を提案する.例えば,職員の職務のみでなく,人柄・適性や仕事量,あるいは勤務状況なども勘案して,上司が適任の部下を選ぶ,と言うような状況を想定している.本提案では,階層型組織やフラット型組織などの組織形態に応じて,多変数公開鍵暗号,及び,楕円エルガマル暗号等を活用しつつ,このような組織間機密通信システムを構成する.As to the application of public key cryptosystem to social organizations, Attribute Based Encryption and Functional Encryption are extensively being developed. In such encryption systems, a sending organization has to identify or decide the qualified receiver in the receiving organization by embedding the capacity of decryption of sending information in the encrypted data or the encryption key. As an example, it is easy for broadcast companies to embed the capacity of viewing of charged television. However, it is often difficult for sending organization to decide the qualified receiver. In such cases, secret communication systems proposed in this presentation seems to be crucial. Although there are various types of social organizations, typically they are divided types; one has hierarchical structure and the other has flat structure. In this paper we propose the Multivariate Public Key Cryptosystem (MPKC) for organizations with hierarchical structure and the elliptic curve cryptosystem for organizations with flat structure. As to MPKC, the structure with Perturbed TSK-MPKC and PQ type TSK-MPKC proposed in Third international conference on Symbolic Computation and Cryptography (SCC 2012, in Castro Urdiales, Spain) can be used.