Getting started¶

The reference SDK lives in python/. It implements the full protocol on software / synthetic test doubles, with AMD SEV-SNP quote verification validated against real hardware.

Install¶

git clone https://github.com/agentrust-io/weight-custody-manifest
cd weight-custody-manifest/python
pip install -e ".[dev]"      # add ".[server]" for the reference KBS server

Build, sign, verify a manifest¶

from wcm import (
    WeightCustodyManifest, Ed25519Signer, generate_ed25519,
    VerificationContext, verify_manifest,
)
import json

manifest = WeightCustodyManifest.model_validate(
    json.load(open("examples/manifest.example.json"))
)

builder, custodian = generate_ed25519(), generate_ed25519()
signed = manifest.with_signatures([
    Ed25519Signer(builder).sign(manifest.unsigned_dict(), role="builder", signer="example-builder"),
    Ed25519Signer(custodian).sign(manifest.unsigned_dict(), role="custodian", signer="opaque-systems"),
])

ctx = VerificationContext()
ctx.add_key(builder.public_bytes)
ctx.add_key(custodian.public_bytes)
print(verify_manifest(signed, ctx).ok)   # True

A manifest is valid only when both the builder and custodian have signed (and the declared sovereign signer, under the sovereign profile). Post-quantum (add_ml_dsa65_key) and hybrid (add_hybrid_key) profiles verify the same way.

Gate a key release¶

from wcm import KeyBrokerService, SoftwareProvider, manifest_identity

kbs = KeyBrokerService(
    {manifest.weights_hash: b"the-decryption-key"},
    trusted_manifest_identities={manifest_identity(manifest)},
)
challenge = kbs.issue_challenge()
evidence = SoftwareProvider().produce(
    challenge,
    serving_image_measurement="sha256:" + "5e2d" * 16,
    gpu_measurement="nvidia-rim:driver+vbios golden measurement id",
)
decision = kbs.verify_and_release(manifest, evidence)
print(decision.released)   # True on a passing gate

SoftwareProvider is a mock with no hardware root of trust. For real evidence see snp.py (AMD SEV-SNP, hardware-validated) and the provider auto-selection in _hw_providers.py.

CLI¶

wcm keygen --out builder
wcm sign examples/manifest.example.json --role builder --signer example-builder --key-file builder --out signed.json
wcm verify signed.json --key-file builder.pub --key-file custodian.pub

See the python/ README for the full module tour.