Protection of data and delegated keys in digital distribution

Masahiro Mambo, Eiji Okamoto, Kouichi Sakurai

研究成果: 書籍/レポート タイプへの寄稿会議への寄与


A cryptography is quite effective in protecting digital information from unauthorized access. But if a receiver of information is determined after the encryption of the information, e.g. a posted encrypted news is withdrawn by an arbitrary user in open networks, we need an additional mechanism for converting the encrypted information into a form accessible only to an admissible user. Even though such a transformation is done by the consecutive execution of decryption of a ciphertext and re-encryption of a recovered plaintext, an intermediary plaintext may be stolen during the re-encryption. In this paper we examine secure digital distribution systems, information storage system and information provider system, in which encrypted information is directly transformed into a ciphertext of an admissible user. We show that the technique of a proxy cryptosystem is useful for establishing these distribution systems. Proposed protocols can be constructed base on the EIGamal cryptosystem or the RSA cryptosystem. Meanwhile, a blind decryption protocol provides privacy protection with respect to the selection of a ciphertext to be decrypted. In terms of digital distribution it also provides a secure information delivery. An information provider system using a blind decryption protocol possesses a problem such that a decrypting person computes exponentiation for a message freely selected by a requesting person. For such an oracle problem, a solution is known with use of a transformable signature. In this paper we show another measure prohibiting the abuse of the blind decryption protocol.

ホスト出版物のタイトルInformation Security and Privacy -2nd Australasian Conference, ACISP 1997, Proceedings
編集者Josef Pieprzyk, Vijay Varadharajan, Yi Mu
出版社Springer Verlag
ISBN(印刷版)3540632328, 9783540632320
出版ステータス出版済み - 1月 1 1997
イベント2nd Australasian Conference on Information Security and Privacy, ACISP 1997 - Sydney, オーストラリア
継続期間: 7月 7 19977月 9 1997


名前Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)


その他2nd Australasian Conference on Information Security and Privacy, ACISP 1997

!!!All Science Journal Classification (ASJC) codes

  • 理論的コンピュータサイエンス
  • コンピュータ サイエンス(全般)


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