A Blockchain-Envisioned Mailing System

Traditional email systems rely on centralized servers for message storage and routing, making them vulnerable to single points of failure and privacy breaches. While blockchain technology has emerged as a decentralized alternative for internet infrastructure, its application to email systems remains underexplored. This paper fills the gaps by proposing a blockchain-based mailing system that eliminates trusted intermediaries while enhancing privacy. Our approach integrates four key components: (1) the ECIES scheme to ensure end-to-end confidentiality of email content, (2) BIP-32-derived addresses to achieve sender anonymity, (3) stealth addresses to provide receiver k-anonymity, and (4) a broadcast encryption scheme to enable efficient broadcast messaging. Moreover, our design allows the sender to prove membership in the broadcast mailing while preserving anonymity. Further, the proposed system introduces an incentive mechanism that allows recipients to charge fees for incoming emails, effectively discouraging spam. We present a proof-of-concept implementation on the Ethereum blockchain and evaluate its on-chain performance in terms of gas consumption. Experimental results demonstrate the practicality and efficiency of the proposed system.