Blockchain–integrated IoT biometric architecture for secure and decentralized electronic voting

A free and fair mass voting system is the key to all elections in the democratic world. Traditional voting systems, such as paper ballot voting, often face trust issues due to a lack of security and transparency. The electronic voting system (EVM) has emerged as an alternative with several advantages. However, EVM still presents its own set of challenges, including centralization, potential manipulation of software logic, accessibility issues, and a lack of verifiability, among others. To overcome these limitations, this study presents a blockchain-integrated IoT biometric voting architecture that coordinates low-cost biometric acquisition, multimodal voter verification, privacy-preserving pseudonymous identity handling, off-chain biometric protection, and smart-contract-based vote validation within a unified end-to-end election workflow. In the proposed architecture, the system integrates low-cost IoT devices for acquiring voters’ biometric data (face and fingerprint), and robust voter verification is performed through AFIS-based fingerprint matching and InsightFace-based facial recognition with liveness-aware anti-spoofing checks. To strengthen privacy, the system avoids direct on-chain use of the voter’s National ID and instead uses privacy-preserving pseudonymous identity management via encryption and hashing, while sensitive biometric records remain protected in off-chain storage. The proposed architecture defines three primary roles: admin, voter, and candidate. The entire process consists of two main phases: voter registration and voting. During registration, the administrator proceeds with voter registration using forms and biometrics. On election day, voter eligibility is confirmed by matching their live biometric input with the records created during registration. Each submitted vote is validated and written to the Ethereum blockchain via smart contracts. Experimental evaluation demonstrates that the system achieves high biometric performance, achieving 96.09% face-verification accuracy, a configured fingerprint FAR operating point of 0.0001 or 0.01%, an average IoT data transfer time of 6.4 seconds, which can be optimized to 3.2 seconds, a blockchain deployment cost of $113.5, and a per-vote casting cost of approximately $4.06 (at a baseline gas price of 20 Gwei). Combining IoT-based biometrics with blockchain enhances election security, protects privacy, and provides end-to-end transparency through a tamper-proof, trustworthy, and verifiable record of votes.