Authors: Sumanta Chatterjee; Shashidhar G. Koolagudi
Addresses: Department of Computer Science and Engineering, National Institute of Technology, Karnataka Karnataka, 575025, India ' Department of Computer Science and Engineering, National Institute of Technology, Karnataka Karnataka, 575025, India
Abstract: In this paper, a model to share secret information in conjunctive and disjunctive hierarchical access structure using obfuscation is proposed. Indistinguishability Obfuscation is achieved with a context free grammar (CFG) as a mimic function. Obfuscation is used to maintain confidentiality of the message in the presence of a dishonest distributor who is curious to know the secret. A new way to effectively reduce the size of the share is also achieved in this model. First, mimic function is used to convert the statistical profile of the message to a random distribution of words from a chosen paragraph. The frequency distribution of different parts of speech (PoS) components of the obfuscated string is used to build a model for distribution of shares to n people based on the responsibility of the person in a hierarchy. Sharing the information and reconstruction of the original message is also shown. It is also shown that the obfuscation is secure against chosen plain text attack.
Keywords: PoS; parts of speech; hierarchical threshold sharing; CFG; context free grammar; indistinguishability obfuscation; mimic function.
International Journal of Security and Networks, 2017 Vol.12 No.4, pp.241 - 254
Received: 13 May 2016
Accepted: 22 Mar 2017
Published online: 22 Nov 2017 *