Verified Container Specification

Protocol specifications for supply-chain-verified containers.

This repository defines the shared protocol between container image producers (build systems) and consumers (runtimes). Any compliant producer can create images that any compliant consumer can verify.

Overview

┌─────────────────────────────────────────────────────────────────────────┐
│                     VERIFIED CONTAINER PROTOCOL                          │
├─────────────────────────────────────────────────────────────────────────┤
│                                                                          │
│  ┌────────────────┐                      ┌────────────────┐             │
│  │    PRODUCER    │                      │    CONSUMER    │             │
│  │                │                      │                │             │
│  │  Build system  │  ── OCI Image ────►  │  Container     │             │
│  │  that creates  │  ── Attestation ──►  │  runtime that  │             │
│  │  verified      │  ── Trust Store ──►  │  verifies      │             │
│  │  images        │                      │  before exec   │             │
│  └────────────────┘                      └────────────────┘             │
│                                                                          │
│  Examples:                               Examples:                       │
│  • Cerro Torre                           • Svalinn/Vordr                │
│  • Wolfi                                 • Cosign-aware runtimes        │
│  • Any SLSA L3+ builder                  • Policy engines               │
│                                                                          │
└─────────────────────────────────────────────────────────────────────────┘

Specifications

Spec	Description	Status
Attestation Bundle	Format for packaging in-toto attestations with log proofs	Draft
Trust Store	Schema for distributing and managing public keys	Draft
Verification Protocol	Procedure for verifying images before execution	Draft
Transparency Log	Requirements for federated transparency logs	Draft
Trust Store Schema	JSON Schema for trust store validation	Draft

Design Principles

1. Content-Addressed

Everything is identified by cryptographic hash. No mutable references cross the protocol boundary.

2. Stateless

No sessions, tokens, or negotiation. Each verification is independent.

3. Federated Trust

No single point of trust. Threshold signatures and multiple log operators required.

4. Implementation Agnostic

Producers and consumers can be implemented in any language. Only the wire format matters.

Implementations

Producers

• Cerro Torre — Ada/SPARK supply-chain-verified Linux distribution

Consumers

• Svalinn/Vordr — Rust/SPARK container runtime with formal verification

Contributing

Proposals for spec changes should be submitted as pull requests with:

1. Rationale for the change

2. Backwards compatibility analysis

3. Security impact assessment

License

Specifications are dual-licensed under MIT OR Apache-2.0.

Implementations may use any compatible license.