HyperXArray: Low-Power and Compact Memristive Architecture for In-Memory Encryption on Edge

Encryption on large-scale memristor crossbars proves to be challenging due to the spatial and temporal fluctuations of the signals coming from numerous non-idealities. To address this, we utilize Hyperlock, a memristive vector-matrix multiplication accelerator employing hyperdimensional computing for encryption. We demonstrate that stochasticity generated on TiOx memristor crossbars with passive 0T1R arrangement can be decryptable under the appropriate training of a neural network. We present HyperXArray, an architecture for Hyperlock's encryption scheme, that is capable of weight regeneration, and analog/digital encryption without the need for high-resolution Analog-to-Digital Converters (ADCs) and Digital-to-Analog Converters (DACs). We demonstrate 100% decryption accuracy for digital encryption and show that HyperXArray is capable of encryption during analog to digital conversion that reduces the power consumption of ADC by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$50\times$</tex-math></inline-formula>. In digital encryption, we show that HyperXArray reduces energy consumption by up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$10\times$</tex-math></inline-formula> and footprint by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$10-100\times$</tex-math></inline-formula> compared to Field Programmable Gate Array (FPGA) implementations of Advanced Encryption Standard (AES), while maintaining the same level of throughput. Overall, HyperXArray demonstrates its capability to fill the niche for lightweight, noise-resilient encryption on edge with only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.1mm^{2}$</tex-math></inline-formula> footprint and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$60 pJ/bit$</tex-math></inline-formula> energy efficiency.