Setting Up
1. Create Your Vault
When you open the app, you'll be asked for a master password. This password encrypts your local database using Argon2id. Nobody knows the password except you, so don't lose it.
2. Cryptographic Identity
Entropy generates a unique Ed25519 keypair. Your identity is a SHA-3 hash of your public key. This is how you are identified on the network.
3. Connecting to Peers
To chat, share your Identity Hash or your custom nickname with a contact. Once you both add each other, a direct E2EE session is established via the messaging relay.
4. Secure Messaging
All communications use the Double Ratchet algorithm. Every message is individually encrypted, providing perfect forward secrecy.
Detailed FAQ
Is my IP address logged by the relay?
Absolutely not. While any network connection technically involves an IP address for packet delivery, Entropy's messaging relay is specifically configured to never log or store IP addresses. To further enhance your anonymity, Entropy provides built-in support for Tor and SOCKS5 proxies, allowing you to hide your physical location from the relay entirely.
What identifiers are visible to the relay?
To deliver a message, the relay only sees the Sender Identity Hash and the Receiver Identity Hash. These are 256-bit cryptographic strings derived from your public key. To enable our 7-day delivery window, the relay transiently caches encrypted packets associated with those hashes until they are successfully retrieved or expire.
Can I use a nickname instead of the Identity Hash?
Yes! Entropy allows you to set a local nickname that maps to your Identity Hash. This makes it much easier for friends to add you and for you to recognize your contacts, all while maintaining the security of the underlying cryptographic ID.
How does group messaging work?
Groups in Entropy are designed for maximum privacy using Client-Side Fan-out. Instead of relying on the relay to distribute messages, your client handles the distribution to each group member individually. This ensures that the relay remains completely unaware of the group's existence, its members, or its size. This architecture prevents any form of group-level metadata analysis by the infrastructure provider.
How does Entropy handle metadata resistance?
Entropy implements Traffic Normalization. All outbound packets are padded to uniform 1400-byte blocks. The client also sends periodic dummy packets at random intervals to maintain a constant background traffic flow, making it statistically impossible to distinguish between active communication and idle states.
What happens if the relay goes down?
Entropy is designed to be relay-resilient. If the primary relay is unavailable, your messages are queued locally and delivered as soon as connection is restored. If your recipient is offline, Entropy's relay stores messages in a RAM-only temporary queue for 7 days before they are automatically purged.
How does "Autonomous Recovery" work?
Instead of relying on login credentials, Entropy uses PoW-validated session tokens. Once you've authenticated via a computational challenge, your session remains valid for 30 days. Your client stores this token in your secure local vault, allowing you to resume communication instantly upon reopening the app.
How do you protect against future Quantum Computers?
Our implementation of the Signal Protocol (X3DH) is augmented with a post-quantum KEM (Key Encapsulation Mechanism), specifically Kyber-1024. This lattice-based cryptography ensures that your conversations remain secure even against the most powerful future quantum computers.
How is my data encrypted on disk?
Entropy uses SQLCipher for the local message database, utilizing 256-bit AES encryption. The master key for this database is derived from your passphrase using Argon2id, the industry standard for memory-hard password hashing.