— Presentation at STACNS2009 —
August 4, 2009
SAM2009 was held from July 13th to 16th, 2009 in Las Vegas in United States. SAM2009 is an academic conference for information security within WORLDCOMP2009 that consists of various conferences for computer and information technologies. About 80 presentations were made in SAM2009.
STACNS2009 is a special track of SAM09. At STACNS2009, Hitachi, Ltd., Systems Development Laboratory (SDL) made a presentation titled "A Study on Multi-Recipient Encryption for Selective Disclosure," about a security of encryption schemes where a part of a ciphertext is disclosed according to each of multi-recipients selectively. Note that this work has been done by a part of a consignment research of the National Institute on Information and Communications Technology (NICT), Japan, from 2005 to 2007.
Photo 1 Presentation Scene
Fig. 1 Framework of Encryption Schemes
Enlarge
In the consignment research, SDL developed encryption schemes in which a part of a ciphertext is disclosed selectively (Fig. 1), which we call eXtended Multi-Recipient Encryption Schemes (XMRESs), for protecting sensitive information in a document wherever the document is browed. Although partial encryption is known as a technique for disclosing a part of a document selectively, the conventional partial encryption only encrypts a part to be encrypted in a document separately and none consider a formal security model of the partial encryption.
Fig. 2 Definition of the Security Level
Enlarge
In STACNS2009, we proposed a formal security model to evaluate the security of XMRESs and classified the security level according to requirements of an application for XMRESs (Fig. 2). Moreover we compared the proposed security levels with that of known techniques like partial encryptions, broadcast encryption and MRESs (Multi-Recipient Encryption Schemes) and also showed example applications for each security level. The proposed security model enables us to evaluate the security of encryption schemes for sending a ciphertext to multi-recipients according to requirements for an application of the encryption schemes.
Related Links
Researcher itself explains the research theme on information area in detail.
Technical terms related to research themes at SDL are explained.
