The Private Set Intersection (PSI) functionality is valuable which allows different organizations to collaborate in privacy-sensitive environments, and its intersection is highly valuable in analytics. With similar business interests, they can securely compute intersection and its associated values for insightful trends and patterns, which can be considered as intersection-based analysis. However, in such settings, existing PSI schemes are too costly or inadvertently leak sensitive information. Our proposed scheme, Approx-PSI, employs Oblivious Pseudo-Random Functions (OPRF) to provide two-party efficient PSI in a semi-honest model and introduces “noise” into the intersection through differential privacy (DP) to ensure individual privacy. Moreover, the noised intersection for approximate analysis has more flexibility and adaptability in both associated values and desired functions. Compared to existing schemes, Approx-PSI achieves at least$1.5 - 3 \times$faster than the most efficient prior protocols, and up to$77 - 81 \times$faster in certain settings, while reducing communication by at least 90%. Thus, the above benefits make our scheme more practical in the real-world.

Proxy re-encryption (PRE) allows a proxy to transform one ciphertext to another under different encryption keys while keeping the underlying plaintext secret. Because of the ciphertext transformability of PRE, there are many potential private communicating applications of this feature. However, existing PRE schemes are not as full-fledged as expected. The lack of necessary features makes them hard to apply in real-world scenarios. So far, there does not exist a unidirectional multihop PRE scheme with constant decryption efficiency and constant ciphertext size without extensions. Impractical performance and weak scalability also hinder PRE from most real-world applications. In this work, we present a new PRE scheme with secure hardware enclave namedhPRESS(hardware-enhanced PRE scheme using secure enclave). To the best of our knowledge,hPRESSis the first unidirectional multihop PRE scheme which achieves both constant decryption efficiency and constant ciphertext size without extensions. A detailed security analysis demonstrates that our proposal is CCA secure based on the security of the underlying encryption schemes and the secure enclave. We also implement a prototype based on Intel SGX, one of the most popular secure enclave techniques in recent years, and evaluate its performance. The experimental results show that, compared with previous PRE schemes, ourhPRESSis almost one order of magnitude faster in terms of the decryption and transformation.

An optimized lightweight Hardware Trojan (HT)based fault attack is proposed, especially for those resource-constrained environments such as IoT networks. Firstly, Algebraic fault analysis (AFA)is introduced to evaluate different fault models and search for the optimal one. Next, considering the limited resource, a lightweight HT is carefully designed which only flips one bit of the circuit in IoT device. Finally, AFA is applied again to exploit the fault and recover the secret key. An illustrative attack is demonstrated on DES implemented on an FPGA platform, SASEBO-GII. This paper shows that, for single bit fault injection at different rounds or different indexes in the same round, the reduced key search space of DES varies. The proposed technique can search for the optimal fault model, guide the lightweight Hardware Trojan design and automatically recover the secret key. Only one fault is required to recover the secret key of DES, which improves the stealthiness of the designed Hardware Trojan in IoT networks. The entire attack framework can also be applied to other block ciphers such as AES and PRESENT.

The block cipher LED is well suited for resource-constrained scenarios. However, it is vulnerable to the recent fault attacks and different results have been achieved even under the same fault model. In this paper, a comprehensive investigation is conducted on the fault analysis on LED. A novel differential fault analysis is proposed, which is based on the so-called constraint equations. The proposed attack can combine constraint equations at different levels, pushing the differential fault analysis on LED towards its limit in terms of the time complexity, the data complexity and the remained key search space. Under random nibble fault model, SINGLE fault injection can reduce the key search space of LED-64 to 27.90within 1.89s, compared to 217.65within 7 minutes in prior finest contributions. As to DFA on LED-128, TWO fault injections can reduce the key search space to 215.82within 247.88s, compared to 221.96within 16 minutes in previous work. To the best of our knowledge, the scheme that we proposed is the most efficient fault attack on LED cryptosystems.

The Competition for Authenticated Encryption: Security, Applicability, and Robustness (CAESAR) supported by the National Institute of Standards and Technology (NIST) is an ongoing project calling for submissions of authenticated encryption (AE) schemes. The competition itself aims at enhancing both the design of AE schemes and related analysis. The design goal is to pursue new AE schemes that are more secure than advanced encryption standard with Galois/counter mode (AES-GCM) and can simultaneously achieve three design aspects: security, applicability, and robustness. The competition has a total of three rounds and the last round is approaching the end in 2018. In this survey paper, we first introduce the requirements of the proposed design and the progress of candidate screening in the CAESAR competition. Second, the candidate AE schemes in the final round are classified according to their design structures and encryption modes. Third, comprehensive performance and security evaluations are conducted on these candidates. Finally, the research trends of design and analysis of AE for the future are discussed.