Identity & Authentication Protocol

Cipher: Local Trust and Authentication

Cipher does not rely on usernames, emails, or server-side identities. Instead, it uses asymmetric cryptography to establish trust and authenticity—entirely locally, without any centralized verification.

1. Asymmetric Identity

Each user is defined by a cryptographic keypair:

• Private key: Stored locally and never shared.

• Public key: Can be transmitted to others.

This keypair forms the cryptographic identity of the user. The public key is used by recipients to verify the origin and authenticity of encrypted content, while the private key is used to sign and decrypt data.

2. Zero-Knowledge Verification

Messages and files are signed using the sender's private key. The recipient verifies this signature using the sender’s public key. No third party or server is required at any stage of this process. The integrity of the message and the identity of the sender are validated directly by the client device.

3. Channel Concordance

In addition to key signatures, Cipher validates channel concordance: the encryption must match the expected structure and the destination must match the intended public key. This ensures the message was encrypted for the correct recipient and hasn't been rerouted or tampered with.

4. Stateless Authentication

No credentials are exchanged. No login is sent or stored during encryption, transmission, or decryption. Authentication happens through signature validation and structural integrity checks—making impersonation or interception mathematically unfeasible.