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Utsav Banerjee

Publications and source records attributed to Utsav Banerjee.

15 recordsLinked to original sources

Writing a Good Security Paper for ISSCC (2025)

Security is increasingly more important in designing chips and systems based on them, and the International Solid-State Circuits Conference (ISSCC), the leading conference for presenting advances in solid-state circuits and semiconductor technology, is committed to hardware security by establishing the security subcommittee since 2024. In the past two years, the authors of this paper reviewed submissions as members of the Security Subcommittee, a part of International Technical Program Committee (ITPC). This paper aims to encourage high-quality submissions to grow this field in the overall scope of the ISSCC.

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Fast Plaintext-Ciphertext Matrix Multiplication from Additively Homomorphic Encryption

Plaintext-ciphertext matrix multiplication (PC-MM) is an indispensable tool in privacy-preserving computations such as secure machine learning and encrypted signal processing. While there are many established algorithms for plaintext-plaintext matrix multiplication, efficiently computing plaintext-ciphertext (and ciphertext-ciphertext) matrix multiplication is an active area of research which has received a lot of attention. Recent literature have explored various techniques for privacy-preserving matrix multiplication using fully homomorphic encryption (FHE) schemes with ciphertext packing and Single Instruction Multiple Data (SIMD) processing. On the other hand, there hasn't been any attempt to speed up PC-MM using unpacked additively homomorphic encryption (AHE) schemes beyond the schoolbook method and Strassen's algorithm for matrix multiplication. In this work, we propose an efficient PC-MM from unpacked AHE, which applies Cussen's compression-reconstruction algorithm for plaintext-plaintext matrix multiplication in the encrypted setting. We experimentally validate our proposed technique using a concrete instantiation with the additively homomorphic elliptic curve ElGamal encryption scheme and its software implementation on a Raspberry Pi 5 edge computing platform. Our proposed approach achieves up to an order of magnitude speedup compared to state-of-the-art for large matrices with relatively small element bit-widths. Extensive measurement results demonstrate that our fast PC-MM is an excellent candidate for efficient privacy-preserving computation even in resource-constrained environments.

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A Unified Hardware Accelerator for Fast Fourier Transform and Number Theoretic Transform

The Number Theoretic Transform (NTT) is an indispensable tool for computing efficient polynomial multiplications in post-quantum lattice-based cryptography. It has strong resemblance with the Fast Fourier Transform (FFT), which is the most widely used algorithm in digital signal processing. In this work, we demonstrate a unified hardware accelerator supporting both 512-point complex FFT as well as 256-point NTT for the recently standardized NIST post-quantum key encapsulation and digital signature algorithms ML-KEM and ML-DSA respectively. Our proposed architecture effectively utilizes the arithmetic circuitry required for complex FFT, and the only additional circuits required are for modular reduction along with modifications in the control logic. Our implementation achieves performance comparable to state-of-the-art ML-KEM / ML-DSA NTT accelerators on FPGA, thus demonstrating how an FFT accelerator can be augmented to support NTT and the unified hardware can be used for both digital signal processing and post-quantum lattice-based cryptography applications.

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A High-Performance Curve25519 and Curve448 Unified Elliptic Curve Cryptography Accelerator

In modern critical infrastructure such as power grids, it is crucial to ensure security of data communications between network-connected devices while following strict latency criteria. This necessitates the use of cryptographic hardware accelerators. We propose a high-performance unified elliptic curve cryptography accelerator supporting NIST standard Montgomery curves Curve25519 and Curve448 at 128-bit and 224-bit security levels respectively. Our accelerator implements extensive parallel processing of Karatsuba-style large-integer multiplications, restructures arithmetic operations in the Montgomery Ladder and exploits special mathematical properties of the underlying pseudo-Mersenne and Solinas prime fields for optimized performance. Our design ensures efficient resource sharing across both curve computations and also incorporates several standard side-channel countermeasures. Our ASIC implementation achieves record performance and energy of 10.38 $\mu$s / 54.01 $\mu$s and 0.72 $\mu$J / 3.73 $\mu$J respectively for Curve25519 / Curve448, which is significantly better than state-of-the-art.

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pc-COP: An Efficient and Configurable 2048-p-Bit Fully-Connected Probabilistic Computing Accelerator for Combinatorial Optimization

Probabilistic computing is an emerging quantum-inspired computing paradigm capable of solving combinatorial optimization and various other classes of computationally hard problems. In this work, we present pc-COP, an efficient and configurable probabilistic computing hardware accelerator with 2048 fully connected probabilistic bits (p-bits) implemented on Xilinx UltraScale+ FPGA. We propose a pseudo-parallel p-bit update architecture with speculate-and-select logic which improves overall performance by $4 \times$ compared to the traditional sequential p-bit update. Using our FPGA-based accelerator, we demonstrate the standard G-Set graph maximum cut benchmarks with near-99% average accuracy. Compared to state-of-the-art hardware implementations, we achieve similar performance and accuracy with lower FPGA resource utilization.

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Privacy-Preserving Edge Computing from Pairing-Based Inner Product Functional Encryption

Pairing-based inner product functional encryption provides an efficient theoretical construction for privacy-preserving edge computing secured by widely deployed elliptic curve cryptography. In this work, an efficient software implementation framework for pairing-based function-hiding inner product encryption (FHIPE) is presented using the recently proposed and widely adopted BLS12-381 pairing-friendly elliptic curve. Algorithmic optimizations provide $\approx 2.6 \times$ and $\approx 3.4 \times$ speedup in FHIPE encryption and decryption respectively, and extensive performance analysis is presented using a Raspberry Pi 4B edge device. The proposed optimizations enable this implementation framework to achieve performance and ciphertext size comparable to previous work despite being implemented on an edge device with a slower processor and supporting a curve at much higher security level with a larger prime field. Practical privacy-preserving edge computing applications such as encrypted biomedical sensor data classification and secure wireless fingerprint-based indoor localization are also demonstrated using the proposed implementation framework.

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QuBEC: Boosting Equivalence Checking for Quantum Circuits with QEC Embedding

Quantum computing has proven to be capable of accelerating many algorithms by performing tasks that classical computers cannot. Currently, Noisy Intermediate Scale Quantum (NISQ) machines struggle from scalability and noise issues to render a commercial quantum computer. However, the physical and software improvements of a quantum computer can efficiently control quantum gate noise. As the complexity of quantum algorithms and implementation increases, software control of quantum circuits may lead to a more intricate design. Consequently, the verification of quantum circuits becomes crucial in ensuring the correctness of the compilation, along with other processes, including quantum error correction and assertions, that can increase the fidelity of quantum circuits. In this paper, we propose a Decision Diagram-based quantum equivalence checking approach, QuBEC, that requires less latency compared to existing techniques, while accounting for circuits with quantum error correction redundancy. Our proposed methodology reduces verification time on certain benchmark circuits by up to $271.49 \times$, while the number of Decision Diagram nodes required is reduced by up to $798.31 \times$, compared to state-of-the-art strategies. The proposed QuBEC framework can contribute to the advancement of quantum computing by enabling faster and more efficient verification of quantum circuits, paving the way for the development of larger and more complex quantum algorithms.

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Power-Based Side-Channel Attack for AES Key Extraction on the ATMega328 Microcontroller

We demonstrate the extraction of an AES secret key from flash memory on the ATMega328 microcontroller (the microcontroller used on the popular Arduino Genuino/Uno board). We loaded a standard AVR-architecture AES-128 implementation onto the chip and encrypted randomly chosen plaintexts with several different keys. We measured the chip's power consumption during encryption, correlated observed power consumption with the expected power consumption of the plaintexts with every possible key, and ultimately extracted the 128-bit key used during AES. We describe here our test infrastructure for automated power trace collection, an overview of our correlation attack, sanitization of the traces and stumbling blocks encountered during data collection and analysis, and results of our attack.

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A Low-Power BLS12-381 Pairing Crypto-Processor for Internet-of-Things Security Applications

We present the first BLS12-381 elliptic curve pairing crypto-processor for Internet-of-Things (IoT) security applications. Efficient finite field arithmetic and algorithm-architecture co-optimizations together enable two orders of magnitude energy savings. We implement several countermeasures against timing and power side-channel attacks. Our crypto-processor is programmable to provide the flexibility to accelerate various elliptic curve and pairing-based protocols such as signature aggregation and functional encryption.

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Leaky Nets: Recovering Embedded Neural Network Models and Inputs through Simple Power and Timing Side-Channels -- Attacks and Defenses

With the recent advancements in machine learning theory, many commercial embedded micro-processors use neural network models for a variety of signal processing applications. However, their associated side-channel security vulnerabilities pose a major concern. There have been several proof-of-concept attacks demonstrating the extraction of their model parameters and input data. But, many of these attacks involve specific assumptions, have limited applicability, or pose huge overheads to the attacker. In this work, we study the side-channel vulnerabilities of embedded neural network implementations by recovering their parameters using timing-based information leakage and simple power analysis side-channel attacks. We demonstrate our attacks on popular micro-controller platforms over networks of different precisions such as floating point, fixed point, binary networks. We are able to successfully recover not only the model parameters but also the inputs for the above networks. Countermeasures against timing-based attacks are implemented and their overheads are analyzed.

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A Low-Power Dual-Factor Authentication Unit for Secure Implantable Devices

This paper presents a dual-factor authentication protocol and its low-power implementation for security of implantable medical devices (IMDs). The protocol incorporates traditional cryptographic first-factor authentication using Datagram Transport Layer Security - Pre-Shared Key (DTLS-PSK) followed by the user's touch-based voluntary second-factor authentication for enhanced security. With a low-power compact always-on wake-up timer and touch-based wake-up circuitry, our test chip consumes only 735 pW idle state power at 20.15 Hz and 2.5 V. The hardware accelerated dual-factor authentication unit consumes 8 $μ$W at 660 kHz and 0.87 V. Our test chip was coupled with commercial Bluetooth Low Energy (BLE) transceiver, DC-DC converter, touch sensor and coin cell battery to demonstrate standalone implantable operation and also tested using in-vitro measurement setup.

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Sapphire: A Configurable Crypto-Processor for Post-Quantum Lattice-based Protocols

Public key cryptography protocols, such as RSA and elliptic curve cryptography, will be rendered insecure by Shor's algorithm when large-scale quantum computers are built. Cryptographers are working on quantum-resistant algorithms, and lattice-based cryptography has emerged as a prime candidate. However, high computational complexity of these algorithms makes it challenging to implement lattice-based protocols on low-power embedded devices. To address this challenge, we present Sapphire - a lattice cryptography processor with configurable parameters. Efficient sampling, with a SHA-3-based PRNG, provides two orders of magnitude energy savings; a single-port RAM-based number theoretic transform memory architecture is proposed, which provides 124k-gate area savings; while a low-power modular arithmetic unit accelerates polynomial computations. Our test chip was fabricated in TSMC 40nm low-power CMOS process, with the Sapphire cryptographic core occupying 0.28 mm2 area consisting of 106k logic gates and 40.25 KB SRAM. Sapphire can be programmed with custom instructions for polynomial arithmetic and sampling, and it is coupled with a low-power RISC-V micro-processor to demonstrate NIST Round 2 lattice-based CCA-secure key encapsulation and signature protocols Frodo, NewHope, qTESLA, CRYSTALS-Kyber and CRYSTALS-Dilithium, achieving up to an order of magnitude improvement in performance and energy-efficiency compared to state-of-the-art hardware implementations. All key building blocks of Sapphire are constant-time and secure against timing and simple power analysis side-channel attacks. We also discuss how masking-based DPA countermeasures can be implemented on the Sapphire core without any changes to the hardware.

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An Energy-Efficient Reconfigurable DTLS Cryptographic Engine for Securing Internet-of-Things Applications

This paper presents the first hardware implementation of the Datagram Transport Layer Security (DTLS) protocol to enable end-to-end security for the Internet of Things (IoT). A key component of this design is a reconfigurable prime field elliptic curve cryptography (ECC) accelerator, which is 238x and 9x more energy-efficient compared to software and state-of-the-art hardware respectively. Our full hardware implementation of the DTLS 1.3 protocol provides 438x improvement in energy-efficiency over software, along with code size and data memory usage as low as 8 KB and 3 KB respectively. The cryptographic accelerators are coupled with an on-chip low-power RISC-V processor to benchmark applications beyond DTLS with up to two orders of magnitude energy savings. The test chip, fabricated in 65 nm CMOS, demonstrates hardware-accelerated DTLS sessions while consuming 44.08 uJ per handshake, and 0.89 nJ per byte of encrypted data at 16 MHz and 0.8 V.

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An Energy-Efficient Reconfigurable DTLS Cryptographic Engine for End-to-End Security in IoT Applications

This paper presents a reconfigurable cryptographic engine that implements the DTLS protocol to enable end-to-end security for IoT. This implementation of the DTLS engine demonstrates 10x reduction in code size and 438x improvement in energy-efficiency over software. Our ECC primitive is 237x and 9x more energy-efficient compared to software and state-of-the-art hardware respectively. Pairing the DTLS engine with an on-chip RISC-V allows us to demonstrate applications beyond DTLS with up to 2 orders of magnitude energy savings.

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An Energy-Efficient Configurable Lattice Cryptography Processor for the Quantum-Secure Internet of Things

This paper presents a configurable lattice cryptography processor which enables quantum-resistant security protocols for IoT. Efficient sampling architectures, coupled with a low-power SHA-3 core, provide two orders of magnitude energy savings over software. A single-port RAM-based NTT architecture is proposed, which provides ~124k-gate area savings. This is the first ASIC implementation which demonstrates multiple lattice-based protocols proposed for NIST post-quantum standardization.

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