Privacy-preserving Attribute Based Searchable Encryption

Attribute Based Encryption (ABE) is a promising public-key cryptographic primitive that can be used for cryptographically enforced access control in untrusted storage. Storing data on untrusted storage not only requires data security for data owners but also poses data protection from untrusted storage server. To address this important requirement, Anonymous Attribute Based Encryption (AABE) is a suitable primitive that provides users to access data from untrusted storage without revealing their identities. At the same time user data can be stored in untrusted storage in an encrypted form. While storing data in an encrypted form, keyword-based query search (and data retrieval) is a challenging research problem. In this paper we present an anonymous attribute based searchable encryption (ASBE) scheme which facilitates user to retrieve only a subset of documents pertaining to his chosen keyword(s). User can upload documents in public cloud in an encrypted form, search documents based on keyword(s) and retrieve documents without revealing his identity. The scheme is proven secure under the selective ciphertextpolicy and chosen plaintext attack (IND-sCP-CPA) model and selective ciphertext-policy and chosen keyword attack (IND-sCP-CKA) model. The scheme requires small storage for user’s decryption key and reduced computation for decryption in comparison to other schemes.