Executive Summary: Entropy is a native, post-quantum communication suite designed to operate in an environment of total surveillance. The protocol achieves Zero-Knowledge Routing through a hardened relay architecture and a Rust-driven client core. By extending the industry-standard, open-source Signal Protocol with post-quantum cryptography (X3DH+PQ and Double Ratchet), Entropy ensures that content, identity, and social graphs remain forensically isolated. Note: Entropy is currently in private beta for desktop; mobile clients are in development.
Entropy abandons centralized accounts and PII-linked identity anchors. Every user exists as a 256-bit entropy string, devoid of links to hardware, network topography, or legal identity.
Users are addressed via the SHA-256 hash of their Public Identity Key. This ensures that the relay can route messages using only a blind mathematical identifier, never obtaining access to the underlying public keys until a session is initiated.
To facilitate human-readable discovery without central coordination, Entropy allows users to register Nicknames. Nickname registration is backed by difficulty-scaled Proof-of-Work (varying by name length) to prevent mass "squatting" or name-impersonation by automated bots.
Entropy leverages a hybrid cryptographic approach, wrapping classical elliptic curve security within NIST-finalist lattice-based algorithms to achieve Post-Quantum Security.
Entropy establishes pairwise sessions via Signal Protocol's Extended Triple Diffie-Hellman (X3DH) enhanced with Post-Quantum Key Encapsulation (Kyber1024). This ensures that even if classical cryptography is broken, the session remains shielded by the PQ layer.
To prevent Sybil attacks and network-level spam, specific state-changing operations (Identity Registration, Key Bundle Uploads) require the solution of a SHA-256 partial collision challenge. The difficulty is dynamic, scaling with relay load.
Entropy uses Signal Protocol's Double Ratchet algorithm for continuous key evolution. Each message sent or received advances both a symmetric-key ratchet (chain keys) and an ephemeral Diffie-Hellman ratchet for asymmetric key agreement.
Chain keys advance with every message, generating unique message keys that are never reused. This ensures that even if a message key is compromised, it cannot be used to decrypt past or future messages.
Integrity Check: The Double Ratchet and message chaining provide implicit integrity - any tampering with message order or content will cause decryption failure or break the session state, allowing the recipient to detect attacks.
In modern surveillance, who you are talking to is more valuable than what you are saying. Entropy treats metadata as a primary threat vector.
Relay nodes facilitate connections without logical awareness of the sender. Entropy uses Signal Protocol's Sealed Sender concept where the sender's identity is encrypted within the innermost layer, readable only by the recipient. The relay validates structural authentication but never learns the sender's identity hash.
Every packet leaving an Entropy node is padded with random noise to exactly 1536 bytes. Combined with Pacing Jitter (10-50ms randomized delays) and constant 1.5KB traffic every 500ms , this makes it mathematically impossible for an ISP or network observer to infer message types or activity patterns through size and timing analysis.
Server responses are padded to exactly 1536 bytes using random whitespace to prevent size-based analysis. Combined with random timing jitter (10-50ms delays), this makes it difficult for network observers to correlate message types or infer activity patterns.
When a client needs to fetch public key bundles to initiate a conversation, it doesn't request just the target user's keys. Instead, it simultaneously requests keys for 4 additional random users from the relay. This means the server cannot determine which of the 5 users the client actually intends to communicate with, providing further masking
Entropy supports optionally routing all traffic through Tor or custom SOCKS5 proxies. This provides network-level anonymity by:
Combined Protection: When used together, Tor routing + decoy fetching + sealed sender creates a multi-layered anonymity system where neither the network, the relay, nor traffic analysts can determine who is communicating with whom.
Security is enforced through physical and process-level boundaries, with additional protections against device compromise.
The Entropy Desktop client uses a multi-process architecture. The UI is physically isolated from the cryptographic core. Private keys never enter the UI memory space, protecting them from UI-based vulnerabilities or malicious browser extensions.
Message history is stored in an encrypted SQLCipher database. This binds your encrypted data to your password; making even access to your message history impossible without your app password.
Entropy provides two emergency data destruction mechanisms:
Note: These wipes are permanent and irreversible. Since Entropy stores no data on servers, once wiped locally, your data is gone forever.
Entropy utilizes Signal Protocol's Sender Key Groups for efficient group communications. This ensures that compromising one member's session key does not expose the entire group history. Each group member maintains a sender key that is used to encrypt messages for all group participants. This provides strong forward secrecy and post-compromise security while remaining bandwidth-efficient compared to pairwise encryption.
The Entropy Relay is designed for non-persistence. It functions more like a blind light-switch than a server.