Intel SGX provides confidentiality and integrity of a program running within the confines of an enclave, and is expected to enable valuable security applications such as private information retrieval. This paper is concerned with the security aspects of SGX in accessing a key system resource, files. Through concrete attack scenarios, we show that all existing SGX filesystems are vulnerable to either system call snooping, page fault, or cache based side-channel attacks. To address this security limitations in current SGX filesystems, we present OBLIVIATE, a data oblivious filesystem for Intel SGX. The key idea behind OBLIVIATE is in adapting the ORAM protocol to read and write data from a file within an SGX enclave. OBLIVIATE redesigns the conceptual components of ORAM for SGX environments, and it seamlessly supports an SGX program without requiring any changes in the application layer. OBLIVIATE also employs SGX-specific defenses and optimizations in order to ensure complete security with acceptable overhead. The evaluation of the prototype of OBLIVIATE demonstrated its practical effectiveness in running popular server applications such as SQLite and Lighttpd, while also achieving a throughput improvement of 2×-8× over a baseline ORAM-based solution, and less than 2× overhead over an in-memory SGX filesystem.

In this paper we present the results of the Unconstrained Ear Recognition Challenge (UERC), a group benchmarking effort centered around the problem of person recognition from ear images captured in uncontrolled conditions. The goal of the challenge was to assess the performance of existing ear recognition techniques on a challenging large-scale dataset and identify open problems that need to be addressed in the future. Five groups from three continents participated in the challenge and contributed six ear recognition techniques for the evaluation, while multiple baselines were made available for the challenge by the UERC organizers. A comprehensive analysis was conducted with all participating approaches addressing essential research questions pertaining to the sensitivity of the technology to head rotation, flipping, gallery size, large-scale recognition and others. The top performer of the UERC was found to ensure robust performance on a smaller part of the dataset (with 180 subjects) regardless of image characteristics, but still exhibited a significant performance drop when the entire dataset comprising 3, 704 subjects was used for testing.

Program obfuscation is a popular cryptographic construct with a wide range of uses such as IP theft prevention. Although cryptographic solutions for program obfuscation impose impractically high overheads, a recent breakthrough leveraging trusted hardware has shown promise. However, the existing solution is based on special-purpose trusted hardware, restricting its use-cases to a limited few. In this paper, we first study if such obfuscation is feasible based on commodity trusted hardware, Intel SGX, and we observe that certain important security considerations are not afforded by commodity hardware. In particular, we found that existing obfuscation/obliviousness schemes are insecure if directly applied to Intel SGX primarily due to side-channel limitations. To this end, we present OBFUSCURO, the first system providing program obfuscation using commodity trusted hardware, Intel SGX. The key idea is to leverage ORAM operations to perform secure code execution and data access. Initially, OBFUSCURO transforms the regular program layout into a side-channelsecure and ORAM-compatible layout. Then, OBFUSCURO ensures that its ORAM controller performs data oblivious accesses in order to protect itself from all memory-based side-channels. Furthermore, OBFUSCURO ensures that the program is secure from timing attacks by ensuring that the program always runs for a pre-configured time interval. Along the way, OBFUSCURO also introduces a systematic optimization such as register-based ORAM stash. We provide a thorough security analysis of OBFUSCURO along with empirical attack evaluations showing that OBFUSCURO can protect the SGX program execution from being leaked by access pattern-based and timing-based channels. We also provide a detailed performance benchmark results in order to show the practical aspects of OBFUSCURO.

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