Chatterjee, S.Koolagudi, S.G.2026-02-052017International Journal of Security and Networks, 2017, 12, 4, pp. 241-25417478405https://doi.org/10.1504/IJSN.2017.088124https://idr.nitk.ac.in/handle/123456789/25730In 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. © © 2017 Inderscience Enterprises Ltd.Context free grammarsPoloniumSyntacticsFrequency distributionsHierarchical threshold sharingIndistinguishabilityMimic functionParts of speechRandom distributionSecret informationSecret sharing schemesInformation dissemination