Research On Attribute-Based Encryption With Equality Test

Along with the rapid development of cloud computing and big data,data privacy becomes more and more significant.To protect the data security,organizations or users tend to store their data in encrypted form.As a part of cryptography,public key encryption(PKE)has a good applicability and flexibility,which plays an important role in work and daily life.There are many researchers have been attracted to work on it.PEKS has a good expansibility,public key encryption with equality test(PKEET)is one typical variant of PEKS.And it becomes a research hotspot in recent years.PKEET allows to check whether two different ciphertexts contain the same message without decryption.The first PKEET scheme has no authorization mechanism and it's not secure enough.Based on the first PKEET,the schemes supporting authorization were proposed in following works to improve PKEET's security.However,most of them have some defects,such as the single authorization or complex mechanism.Recently,the notion of attribute based encryption with equality test(ABEET)was proposed to realize the flexible access control,which combines attribute based encryption(ABE)and PKEET.ABEET realizes the flexible authorization of PKEET and it is practical in many situations.However,recent ABEET schemes suffer from low efficiency and low security.What's worse,their constructions are very complex and overweight.In this paper,we deeply study the principle of ABEET to improve its efficiency and security.This paper will discuss with two application scenarios,label classification of encrypted data and secure deduplication.First part,by using secure and efficient ABE technique,we bring in the notion of access policy to realize the access control of PKEET.We give a novel ciphertext-policy attribute based encryption with equality test(CP-ABEET)which has a more concise construction.And our scheme enjoys a better efficiency of key management and a better security.The second part,we use the outsourcing technique to improve computing efficiency of ABEET.The ABE part in ABEET causes one problem that the LSSS and authorization between access structure and attribute set will make it less efficient than normal PKEET schemes.Considering the high computing cost,we use the outsourcing decryption technique to outsource most computing process to a third cloud server.And we propose the outsourced CP-ABEET scheme(OCP-ABEET)with high efficiency in local,which is more practical for users with low bandwidth or mobile terminals.Both CP-ABEET and OCPABEET schemes are proven OW-SAS-CCA and IND-SAS-CCA secure in random oracle model.The third part,secure schemes in standard model.As we know,the security proof in random oracle model is very idealized.Combining with reality,we reconstruct CP-ABEET and OCP-ABEET schemes and present two corresponding schemes named CP-ABEET-ST and OCP-ABEET-ST with high proven security in standard model.By comparison with related schemes,our schemes have more concise constructions which are more practical.Besides,they are more secure and efficient.This research systematically improves the efficiency and security of ABEET by proposing four integrated schemes and security proofs in this paper,which makes ABEET more practical for secure data classification and deduplication.This paper makes the research on ABEET more complete.