Attribute-Based Equality Test Over Encrypted Data Without Random Oracles

Abstract

Sensitive data would be encrypted before uploading to the cloud due to the privacy issue. However, how to compare the encrypted data efficiently becomes a problem. Public Key Encryption with Equality Test (PKEET) provides an efficient way to check whether two ciphertexts (of possibly different users) contain the same message without decryption. As an enhanced variant, Attribute-based Encryption with Equality Test (ABEET) provides a flexible mechanism of authorization on the equality test. Most of the existing ABEET schemes are only proved to be secure in the random oracle model. Their security, however, would not be guaranteed if random oracles are replaced with real-life hash functions. In this work, we propose a construction of CP-ABEET scheme and prove its security based on some reasonable assumptions in the standard model. We then show how to modify the scheme to outsource complex computations in decryption and equality test to a third-party server in order to support thin clients. INDEX TERMS Attribute-based encryption, equality test, outsourced decryption, standard model, deduplication.

A Generic Construction of CCA-Secure Identity-Based Encryption with Equality Test against Insider Attacks

“…The notion of equality test (ET) is not limited to PKE and IBE; it has also been studied in the context of certificateless PKE [23], group PKE [24], signcryption [25], attributebased encryption [26][27][28][29][30], and so on. Similarly, there are several more flexible notions of ET such as all-or-nothing ET [9], fine-grained ET [31,32], delegated ET [33], and so on.…”