Multi-Vt-Based Energy Efficiency Optimization for ASIC Designs of the Double Secure Hash Algorithm Toward a Sustainable Bitcoin Network

The Double Secure Hash Algorithm (DSHA) is utilized in the cryptographic Proof-of-Work (PoW) consensus mechanism of blockchain networks, including many cryptocurrencies and the Bitcoin (BTC) network. The widespread usage of BTC has raised concerns about its environmental impact, as its annual energy consumption and emissions are estimated to be 125.21 TWh and 63.38 million metric tonnes of carbon dioxide equivalent, respectively. As PoW-based blockchain networks expand, fast and energy efficient Application Specific Integrated Circuits (ASICs) that integrate security hash primitives become vital to their sustainability. Low power ASIC design flows targeting the minimization of a circuit’s power consumption may negatively affect its speed, and its overall energy efficiency. In this brief, we propose a novel Multi-threshold Voltage (Multi-Vt) based energy efficiency optimization flow for DSHA designs that reduces their static power consumption without impacting their performed hash rate. When applied to DSHA designs synthesized with a 32 nm CMOS Technology, it reduces their static power consumption by up to 71.1%, and improves their energy efficiency by up to 49.1%. The proposed optimization flow offers prospects of sustainability, if broadly adopted by commercial mining equipment vendors, as it has the potential to almost halve the global energy consumed for BTC mining.