Security Architecture

1. What Privatera Protects Against

• Network Eavesdropping: Text, signalling and Room Call audio use authenticated peer-encrypted sessions. WebRTC calls require DTLS-SRTP and additional AES-256-GCM media encryption. Internet service providers and network observers see only unreadable encrypted traffic.
• A Relay That Cannot Read Message Content: The edge relay routes encrypted frames in volatile memory with no access to message or audio content, no payload inspection, and no application traffic logs.
• Data Breaches & Subpoenas: Because there are no user accounts, central contact directories, or stored message content on the relay, there is no server message archive to breach or seize.
• Impersonation: Cryptographic signatures (`Ed25519`) and authenticated session channels ensure that messages can only originate from the verified peer.

2. Independent 9-Digit Safety Code

To detect Man-in-the-Middle (MitM) attacks during initial pairing, Privatera produces a Short Authentication String (SAS) derived from both parties' authenticated public keys and session parameters, formatted into three readable groups (e.g., 123 456 789). Verified out-of-band, a network attacker gets only a single attempt per pairing with a success probability of 1 in 10⁹ (one in one billion). On mismatch, do not proceed.

3. Fail-Closed Cryptographic Kill Switch

Under Privatera's zero-trust model, security never degrades opportunistically, favoring confidentiality over availability. If any cryptographic verification fails — whether an authentication tag failure, invalid signature or protocol violation — the affected contact’s sessions and call terminate immediately, key material is cleared on a best-effort basis, and no unencrypted or weakened fallback is ever permitted. Duplicate or old media packets are dropped without rendering.

4. Environmental & Device Boundaries

As with any internet service, network-level metadata (IP, timing, size) is visible to network infrastructure; Privatera does not log it. Because the client code is delivered by the service itself, a compromised delivery path is outside the protection scope. Endpoint cryptography operates within the host device: Privatera cannot protect against a compromised operating system, rootkits, keyloggers, malicious browser extensions, or a modified peer client.

5. Device-bound Keys & No Key Escrow

Privatera has no administrative backdoors, master access keys, or key escrow. Device-bound Ed25519 private keys are generated on-device via the browser Web Crypto API (SubtleCrypto), stored in password-encrypted envelopes, and used through non-extractable runtime handles. This is software protection rather than hardware backing. We cannot recover lost keys or decrypt communications.