Abstract
We propose a peer-to-peer messaging system that eliminates the need for trusted third parties. Current electronic mail protocols (SMTP, IMAP) rely on centralized authorities that inherently compromise user privacy through metadata retention and content scanning. Hachimail introduces a double-ratchet encryption mechanism layered over a distributed hash table (DHT) based storage network, ensuring that neither message content nor relationship graphs can be reconstructed by any single entity. By integrating local-first AI models for spam filtering and categorization, we restore user sovereignty without sacrificing modern utility.
01The centralization trap
The fundamental promise of the internet was decentralization. Yet email—the digital equivalent of a public utility—has collapsed into a triopoly of providers. These entities trade free service for total surveillance access.
- Metadata sovereignty: Even "encrypted" services often leak sender/receiver graph data.
- Censorship resistance: Centralized providers can—and do—deplatform users at the protocol level.
- AI training: Personal correspondence is routinely used to train commercial models.
02Architecture overview
Hachimail is not a server; it is a protocol. The network serves as a "dead drop" system where encrypted blobs are deposited and retrieved using ephemeral keys.
[ APPLICATION LAYER ] <-- Web & mobile clients (local AI) ----------------------------------------------------------- [ ENCRYPTION LAYER ] <-- Double-ratchet + ML-KEM (Kyber) ----------------------------------------------------------- [ TRANSPORT LAYER ] <-- QUIC / libp2p streams ----------------------------------------------------------- [ STORAGE LAYER ] <-- Distributed encrypted shards
2.1 Quantum-resistant handshakes
We anticipate the breakdown of RSA-2048 within the decade. Hachimail implements CRYSTALS-Kyber (ML-KEM) for key encapsulation, ensuring that messages sent today cannot be decrypted retroactively by future quantum adversaries ("store now, decrypt later" attacks).
03Identity & anonymity
Identity on Hachimail is decoupled from legal personhood. A user generates an Identity_Key locally. This key signs outgoing messages and reserves a @hachimail.com handle.
Your mail, sealed.
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