End-to-End Encryption & Cryptographic Architecture
How Cockpit enforces zero-knowledge key isolation, AES-256-GCM authenticated stream ciphers, and perfect forward secrecy across every remote session.
Browser Crypto Subsystem
Keys are derived and encrypted locally via W3C WebCrypto. Private keys never leave user RAM in unencrypted form.
Blind Pipe Transport
Encrypted frame payloads pass through Cockpit relays without TLS termination or private key access. Zero inspection capability.
Host Decryption Boundary
Payloads terminate directly at your host's OpenSSH daemon or sandboxed agent. No shared secrets with the central cloud.
AES-256-GCM Authenticated Stream Encryption
Every terminal keystroke, metrics stream, and file transfer moving through Cockpit is protected by AES-256-GCM (Galois/Counter Mode). Unlike unauthenticated ciphers like CBC, GCM provides both high confidentiality and cryptographic message integrity verification.
Each WebSocket packet contains a 96-bit initialization vector (IV) that increments per frame, preventing replay attacks. A 128-bit authentication tag (GMAC) is verified before any packet payload is unpacked by the client or host.
Packet Framing Structure
If even a single bit in the ciphertext is altered during transit across intermediate routers or proxies, GMAC verification fails immediately and the session drops cleanly.
Zero-Knowledge Vault & Non-Custodial Storage
In standard web architectures, users upload their SSH keys or passwords to the vendor's cloud database. If the vendor suffers a database leak, all customer servers are compromised.
Cockpit uses a zero-knowledge client enclave. Server credentials are encrypted locally on your device before they touch any network interface:
Local WebCrypto Keys
Encryption keys are derived using PBKDF2 with 100,000+ rounds inside browser memory. Plaintext keys are never sent to our servers.
Mathematical Inaccessibility
Our database stores only ciphertext blobs. Even with direct database access or physical server possession, Cockpit engineers cannot decrypt your credentials.
Perfect Forward Secrecy (PFS)
Every active connection session generates an ephemeral Elliptic Curve Diffie-Hellman key pair (ECDH over Curve25519 or NIST P-384).
Session keys are never written to disk or preserved across reconnects. If an attacker records encrypted network traffic today and later gains access to a server or client device, they still cannot decrypt recorded past traffic because the ephemeral session keys were destroyed the instant the connection closed.
Session Key Shredding
Upon user logout, disconnect, or window unload, Cockpit triggers zeroization passes across all WebCrypto CryptoKey object handles in volatile browser heap memory, ensuring no residual key remnants remain accessible.
The Blind Relay Transport Model
Cockpit cloud servers act as a blind multiplexer. When your browser communicates with your remote server (whether via direct OpenSSH port 22 or our isolated node agent), our relay nodes behave strictly as packet conduits:
- No TLS Termination of Terminal Data: The SSH cryptographic envelope is negotiated directly between client and host. The relay cannot decrypt the internal PTY stream.
- Zero Command Logging: Our servers never parse or log shell commands, terminal outputs, file names, or environment variables.
- Strict Memory Buffers: Sockets stream in small ring buffers that flush instantly after forwarding, leaving no packet history on relay disks.
Threat Model & Defense in Depth
Our threat model assumes that the network path, intermediary transit routers, and third-party cloud infrastructure are fundamentally untrusted:
Prevented via cryptographic host key fingerprint matching and bidirectional GCM integrity verification.
Zero-knowledge architecture means internal database compromise yields zero plaintext secrets or private keys.
Enforced via Cross-Origin-Opener-Policy: same-origin and strict Content Security Policies.
Built to meet SOC 2 Type II trust principles for data confidentiality, integrity, and availability.
Security without compromise
Connect your infrastructure with cryptographic guarantees. Free forever, zero tracking, non-custodial.