VBW -- Verified Build Witness

Zero-knowledge build integrity verification using SLSA + in-toto + Sigstore.

VBW is a thin, auditable policy layer that enforces independence: if a build requires internal access, private networks, or secrets, VBW treats that as a policy failure. VBW never touches credentials and cannot leak what it never sees.

Status

Check	Description
CI	cargo fmt + clippy + test + audit + deny
License	Apache-2.0
MSRV	1.88.0

Quick Start

Build

cargo build --release

Install External Tools (optional but recommended)

# SLSA verifier
go install github.com/slsa-framework/slsa-verifier/v2/cli/slsa-verifier@latest

# in-toto
pip install in-toto

# Sigstore (cosign)
go install github.com/sigstore/cosign/v2/cmd/cosign@latest

Verify the Example Bundle

The example runs without external tooling:

./target/release/vbw verify examples/minimal-bundle \
    --no-external --dry-run --slsa-mode schema-only
cat examples/minimal-bundle/vbw/report.json

Verify a Real Bundle (full mode)

vbw verify ./bundle \
    --artifact ./bundle/myapp \
    --source-uri github.com/org/repo

Inspect an Attestation

vbw show \
    --attestation bundle/vbw/vbw-attestation.json \
    --sigstore-bundle bundle/vbw/vbw-attestation.sigstore.bundle

Bundle Structure

bundle/
  provenance.json          # SLSA provenance
  layout.json              # in-toto layout
  links/                   # in-toto attestations (*.link)
  artifacts/               # (optional) binaries to verify
  vbw-policy.json          # (optional) custom policy
  vbw/                     # VBW output
    vbw-attestation.json
    vbw-attestation.sigstore.bundle
    report.json

Policy Configuration

Create vbw-policy.json (see vbw-policy.json.example):

{
  "allowed_builder_prefixes": [
    "https://github.com/",
    "https://gitlab.com/"
  ],
  "builder_allowlist_is_warning": true,
  "forbid_private_network_refs": true,
  "forbid_secrets": true,
  "require_digests": true
}

Development

# Run all quality gates (mirrors CI)
make check

# Individual targets
make fmt         # Check formatting
make clippy      # Lint
make test        # Tests (debug + release)
make audit       # Security audit
make deny        # License/ban/advisory/source checks
make build       # Debug build
make release     # Release build

Security Posture

VBW is designed for deployment in regulated environments and follows RustSec best practices:

• Zero unsafe code: #![forbid(unsafe_code)] -- cannot be overridden
• Zero known advisories: cargo-audit + cargo-deny on every PR + daily
• No .unwrap() in production: clippy::unwrap_used = "deny"
• No FFI/C dependencies: OpenSSL is explicitly banned in deny.toml
• Linear-time regex: No catastrophic backtracking (ReDoS) possible
• Symlink-safe I/O: All untrusted file reads reject symlinks
• Size-bounded inputs: Enforced limits on all untrusted data
• No shell invocation: External tools called via std::process::Command
• Secret redaction: Tool stderr is sanitized before inclusion in reports

Repository Standards

This repository follows banking-grade operational standards:

• Pinned CI actions: All GitHub Actions pinned to SHA, not mutable tags
• Supply chain policy: cargo-deny enforces license, advisory, ban, and source rules
• Automated audits: Daily cargo-audit + cargo-deny via scheduled workflow
• Dependency updates: Dependabot for Cargo and GitHub Actions
• DCO enforcement: All commits require Developer Certificate of Origin sign-off
• Code ownership: CODEOWNERS enforces mandatory review by domain experts
• Branch protection: Requires 2 approvals, signed commits, linear history
• SBOM generation: CycloneDX SBOM included in every release
• Reproducible toolchain: rust-toolchain.toml pins compiler version
• Strict formatting: rustfmt.toml + clippy.toml with zero-warning policy

Documentation

• ARCHITECTURE.md -- Composition model and threat boundaries
• AUDIT-BOUNDARY.md -- IP delineation and third-party audit scope
• SECURITY.md -- Vulnerability disclosure and security model
• CONTRIBUTING.md -- Contribution guidelines and quality requirements
• CODE_OF_CONDUCT.md -- Community standards
• examples/DEMO.md -- Reproducible demo workflow
• DCO -- Developer Certificate of Origin

License

Apache-2.0. See LICENSE and NOTICE.