VMEO: Vector Modeling Errors and Operands for Approximate adders

Approximate computing techniques are extensively used in computationally intensive applications. Addition architecture being the basic component of computational unit, has received a lot of interest from approximate computing community. Approximate adders are designed with the motivation to reduce area, power and delay of their accurate versions at the cost of bounded loss in accuracy. A major class of approximate adders are implemented using binary logic circuits that operate with a high degree of predictability and speculation. This paper is one of the early attempt to vector model error values that occur in approximate architectures and the inputs fed to them. In this paper, we propose two vectors namely Error Vectors (EVs) and the Input Conditioning Vectors (ICVs) that will form the mathematical foundation of several probabilistic error evaluation methodologies. In other words, the suggested vectors can be used to develop assessment methods to measure the performance of approximate circuits. Our proposed vectors when utilised to analyze approximate circuits, will provide a descriptive idea about (i) chances of error generation and propagation, (ii) the amount of error at specific bit locations and its impact on overall result. This is however not conceivable with existing state-of-the-art methodologies

B2T: The Third Logical Value of a Bit

Modern computing systems predominantly operate on the binary number system that accepts only ‘0’ or ‘1’ as logical values leading to computational homogeneity. But this helps in creating leakage patterns that can be exploited by adversaries to carry out hardware and software-level attacks. Recent research has shown that ternary systems, operating on three logical values (‘0′, ‘1\u27, and ‘z\u27) can surpass binary systems in terms of performance and security. In this paper, we first propose a novel approach that assigns logical values based on the direction of current flow within a conducting element, rather than relying on the voltage scale. Furthermore, we also present the mathematical models for each ternary gate

Sorting Attacks Resilient Authentication Protocol for CMOS Image Sensor Based PUF

Physically Unclonable Functions (PUFs) have emerged as a viable and cost-effective method for device authentication and key generation. Recently, CMOS image sensors have been exploited as PUF for hardware fingerprinting in mobile devices. As CMOS image sensors are readily available in modern devices such as smartphones, laptops etc., it eliminates the need for additional hardware for implementing a PUF structure. In ISIC2014, an authentication protocol has been proposed to generate PUF signatures using a CMOS image sensor by leveraging the fixed pattern noise (FPN) of certain pixel values. This makes the PUF candidate an interesting target for adversarial attacks. In this work, we testify that a simple sorting attack and a win-rate (WR) based sorting attack can be launched in this architecture to predict the PUF response for given a challenge. We also propose a modified authentication protocol as a countermeasure to make it resilient against simple sorting and WR sorting attacks. The proposed work reduces the accuracy of prediction due to simple sorting attack and WR sorting attack by approximately 14% compared to the existing approach

On the Validity of Spoofing Attack Against Safe is the New Smart

Recently, a light-weight authenticated key-exchange (AKE) scheme has been proposed. The scheme provides mutual authentication. It is asymmetric in nature by delegating complex cryptographic operations to resource-equipped servers, and carefully managing the workload on resource-constrained Smart meter nodes by using Physically Unclonable Functions. The prototype Smart meter built using commercial-off-the-shelf products is enabled with a low-cost countermeasure against load-modification attacks, which goes side-by-side with the proposed protocol. An attack against this AKE scheme has been recently proposed claiming that the server can be breached to mount spoofing attacks. It relies on the assumption that the result of an attack against authenticated key-exchange protocol is determined before the attacker learns the session key. In this short paper, we discuss the attack’s validity and describe the misinterpretation of the AKE protocol’s security definition

A PUF-based Secure Communication Protocol for IoT

Security features are of paramount importance for IoT, and implementations are challenging given the resource-constrained IoT set-up. We have developed a lightweight identity-based cryptosystem suitable for IoT, to enable secure authentication and message exchange among the devices. Our scheme employs Physically Unclonable Function (PUF), to generate the public identity of each device, which is used as the public key for each device for message encryption. We have provided formal proofs of security in the Session Key security and Universally Composable Framework of the proposed protocol, which demonstrates the resilience of the scheme against passive as well as active attacks. We have demonstrated the set up required for the protocol implementation and shown that the proposed protocol implementation incurs low hardware and software overhead

Physically Related Functions: A New Paradigm for Light-weight Key-Exchange

In this paper, we propose a novel concept named Physically Related Function(PReF) which are devices with hardware roots of trust. It enables secure key-exchange with no pre-established/embedded secret keys. This work is motivated by the need to perform key-exchange between lightweight resource-constrained devices. We present a proof-of-concept realization of our contributions in hardware using FPGAs

A Tale of Twin Primitives: Single-chip Solution for PUFs and TRNGs

Physically Unclonable Functions (PUFs) and True Random Number Generators (TRNGs) are two highly useful hardware primitives to build up the root-of-trust for an embedded device. PUFs are designed to offer repetitive and instance-specific randomness, whereas TRNGs are expected to be invariably random. In this paper, we present a dual-mode PUF-TRNG design that utilises two different hardware-intrinsic properties, i.e. oscillation frequency of the Transition Effect Ring Oscillator (TERO) cell and the propagation delay of a buffer within the cell to serve the purpose of both PUF and TRNG depending on the exact requirement of the application. The PUF design is also proposed to have a built-in resistance to machine learning (ML) and deep learning (DL) attacks, whereas the TRNG exhibits sufficient randomness

Exploiting Safe Error based Leakage of RFID Authentication Protocol using Hardware Trojan Horse

Radio-Frequency Identification tags are used for several applications requiring authentication mechanisms, which if subverted can lead to dire consequences. Many of these devices are based on low-cost Integrated Circuits which are designed in off-shore fabrication facilities and thus raising concerns about their trust. Recently, a lightweight entity authentication protocol called LCMQ was proposed, which is based on Learning Parity with Noise, Circulant Matrix, and Multivariate Quadratic problems. This protocol was proven to be secure against Man-in-the-middle attack and cipher-text only attacks. In this paper, we show that in the standard setting, although the authentication uses two $m$ bit keys, $\mathbf{K_1}$ and $\mathbf{K_2}$, knowledge of only $\mathbf{K_2}$ is sufficient to forge the authentication. Based on this observation, we design a stealthy malicious modification to the circuitry based on the idea of Safe-errors to leak $\mathbf{K_2}$ and thus can be used to forge the entire authentication mechanism. We develop a Field Programmable Gate Array prototype of the design which is extremely lightweight and can be implemented using four Lookup tables

PUF+IBE: Blending Physically Unclonable Functions with Identity Based Encryption for Authentication and Key Exchange in IoTs

Physically Unclonable Functions (PUFs) promise to be a critical hardware primitive to provide unique identities to billions of connected devices in Internet of Things (IoTs). In traditional authentication protocols a user presents a set of credentials with an accompanying proof such as password or digital certificate. However, IoTs need more evolved methods as these classical techniques suffer from the pressing problems of password dependency and inability to bind access requests to the “things” from which they originate. Additionally, the protocols need to be lightweight and heterogeneous. Although PUFs seem promising to develop such mechanism, it puts forward an open problem of how to develop such mechanism without needing to store the secret challenge-response pair (CRP) explicitly at the verifier end. In this paper, we develop an authentication and key exchange protocol by combining the ideas of Identity based Encryption (IBE), PUFs and Key-ed Hash Function to show that this combination can help to do away with this requirement. The security of the protocol is proved formally under the Session Key Security and the Universal Composability Framework. A prototype of the protocol has been implemented to realize a secured video surveillance camera using a combination of an Intel Edison board, with a Digilent Nexys-4 FPGA board consisting of an Artix-7 FPGA, together serving as the IoT node. We show, though the stand-alone video camera can be subjected to man-in-the-middle attack via IP-spoofing using standard network penetration tools, the camera augmented with the proposed protocol resists such attacks and it suits aptly in an IoT infrastructure making the protocol deployable for the industry