A Trusted Execution Enclave within Dual-Confidential Computing Hardware

In confidential computing (CC), the program and the data are expected to be provided by the same user. However, there has been a rapid rise in the number of workloads where the program and the data come from distinct users wanting to maintain confidentiality from each other. This disclosure describes techniques to create trusted execution enclaves (TEE) within dual-confidential computing (DCC) hardware. In DCC-TEE, the program is encrypted using a key controlled by the program owner. The user data is encrypted using a key controlled by the user. The encrypted program and the encrypted user data are both sent to the enclave, where the program can access user data in plaintext but is prevented from sending user data outside the enclave. The program can only send back encrypted data to the user with the key owned by the user. The program and the data are thus isolated from each other

Optimal Checkpointing for Secure Intermittently-Powered IoT Devices

Energy harvesting is a promising solution to power Internet of Things (IoT) devices. Due to the intermittent nature of these energy sources, one cannot guarantee forward progress of program execution. Prior work has advocated for checkpointing the intermediate state to off-chip non-volatile memory (NVM). Encrypting checkpoints addresses the security concern, but significantly increases the checkpointing overheads. In this paper, we propose a new online checkpointing policy that judiciously determines when to checkpoint so as to minimize application time to completion while guaranteeing security. Compared to state-of-the-art checkpointing schemes that do not account for the overheads of encrypted checkpoints we improve execution time up to 1.4x.Comment: ICCAD 201

Execution Integrity with In-Place Encryption

Instruction set randomization (ISR) was initially proposed with the main goal of countering code-injection attacks. However, ISR seems to have lost its appeal since code-injection attacks became less attractive because protection mechanisms such as data execution prevention (DEP) as well as code-reuse attacks became more prevalent. In this paper, we show that ISR can be extended to also protect against code-reuse attacks while at the same time offering security guarantees similar to those of software diversity, control-flow integrity, and information hiding. We present Scylla, a scheme that deploys a new technique for in-place code encryption to hide the code layout of a randomized binary, and restricts the control flow to a benign execution path. This allows us to i) implicitly restrict control-flow targets to basic block entries without requiring the extraction of a control-flow graph, ii) achieve execution integrity within legitimate basic blocks, and iii) hide the underlying code layout under malicious read access to the program. Our analysis demonstrates that Scylla is capable of preventing state-of-the-art attacks such as just-in-time return-oriented programming (JIT-ROP) and crash-resistant oriented programming (CROP). We extensively evaluate our prototype implementation of Scylla and show feasible performance overhead. We also provide details on how this overhead can be significantly reduced with dedicated hardware support

SOFIA : software and control flow integrity architecture

Microprocessors used in safety-critical systems are extremely sensitive to software vulnerabilities, as their failure can lead to injury, damage to equipment, or environmental catastrophe. This paper proposes a hardware-based security architecture for microprocessors used in safety-critical systems. The proposed architecture provides protection against code injection and code reuse attacks. It has mechanisms to protect software integrity, perform control flow integrity, prevent execution of tampered code, and enforce copyright protection. We are the first to propose a mechanism to enforce control flow integrity at the finest possible granularity. The proposed architectural features were added to the LEON3 open source soft microprocessor, and were evaluated on an FPGA running a software benchmark. The results show that the hardware area is 28.2% larger and the clock is 84.6% slower, while the software benchmark has a cycle overhead of 13.7% and a total execution time overhead of 110% when compared to an unmodified processor

Reuse It Or Lose It: More Efficient Secure Computation Through Reuse of Encrypted Values

Two-party secure function evaluation (SFE) has become significantly more feasible, even on resource-constrained devices, because of advances in server-aided computation systems. However, there are still bottlenecks, particularly in the input validation stage of a computation. Moreover, SFE research has not yet devoted sufficient attention to the important problem of retaining state after a computation has been performed so that expensive processing does not have to be repeated if a similar computation is done again. This paper presents PartialGC, an SFE system that allows the reuse of encrypted values generated during a garbled-circuit computation. We show that using PartialGC can reduce computation time by as much as 96% and bandwidth by as much as 98% in comparison with previous outsourcing schemes for secure computation. We demonstrate the feasibility of our approach with two sets of experiments, one in which the garbled circuit is evaluated on a mobile device and one in which it is evaluated on a server. We also use PartialGC to build a privacy-preserving "friend finder" application for Android. The reuse of previous inputs to allow stateful evaluation represents a new way of looking at SFE and further reduces computational barriers.Comment: 20 pages, shorter conference version published in Proceedings of the 2014 ACM SIGSAC Conference on Computer and Communications Security, Pages 582-596, ACM New York, NY, US