ZTOP — Zero Trust Transfer Orchestration Protocol

ZTOP is a Python reference implementation of the Zero Trust Transfer Orchestration Protocol, an Application Layer (OSI Layer 7) protocol for cryptographically authenticated, continuously attested peer-to-peer file transfer in Zero Trust Architectures (ZTA).

Overview

Traditional file transfer protocols (SFTP, FTP) authenticate once and establish a trusted channel. ZTOP integrates every Zero Trust principle natively into the protocol itself:

Installation

pip install ztop

Requires Python 3.11 or later.

Development installation

git clone https://github.com/sripad2020/ztop-research
cd ztop-research
pip install -e ".[dev]"

Quick Start

Start a gateway server

ztop server
# or with custom address
ztop server --host 0.0.0.0 --port 7890 --log-level DEBUG

Connect and upload a file

ztop client --file /path/to/document.pdf
# or specify target
ztop client --host 10.0.0.5 --port 7890 --file /path/to/file --device-id my-laptop --org-id acme-corp

Run the self-contained demo (no setup required)

ztop demo

Run the advanced X.509 certificate demo

ztop cert-demo

Check version

ztop version

Session Lifecycle

Client                           Gateway
  |                                 |
  |-------- HELLO ----------------> |   Phase 1: Discovery
  |<------- DISCOVER --------------- |
  |-------- REGISTER -------------> |   Phase 2: Identity
  |<------- IDENTITY_REQUEST ------- |   Ed25519 challenge issued
  |-------- IDENTITY_RESPONSE ----> |   64-byte sig + 32-byte pubkey
  |-------- TRUST_REQUEST --------> |   Phase 3: Device Posture
  |<------- TRUST_RESPONSE --------- |   Score assigned
  |-------- POLICY_REQUEST -------> |   Phase 4: Policy Evaluation
  |<------- POLICY_RESPONSE -------- |   6-check authorization
  |-------- CAPABILITY_NEGOTIATE -> |   Phase 5: Negotiation
  |<------- CAPABILITY_NEGOTIATE --- |   chunk_size, window
  |-------- SESSION_CREATE -------> |   Phase 6: Session Active
  |<------- SESSION_ACCEPT --------- |
  |-------- TRANSFER_REQUEST -----> |   Phase 7: File Transfer
  |<------- TRANSFER_START --------- |
  |-------- TRANSFER_CHUNK x N ---> |   PAYLOAD_ENCRYPTED required
  |<------- TRANSFER_ACK ----------- |   per-chunk Merkle verification
  |-------- TRANSFER_COMPLETE ----> |   Phase 8: Audit
  |<------- INTEGRITY_VERIFY ------- |   SHA-3-512 file check
  |<------- AUDIT_COMMIT ----------- |   ECDSA-P384 sealed record
  |-------- SESSION_CLOSE --------> |   Phase 9: Graceful Close
  |<------- SESSION_CLOSE ---------- |

Architecture

ztop/
  protocol/       Binary wire format (packet.py, states.py, messages.py)
  core/           Session state management (session.py)
  engines/
    trust_engine.py       Device posture scoring (100-point scale)
    policy_engine.py      6-check transfer authorization
    heartbeat_engine.py   Continuous 8-check attestation
    merkle_engine.py      Binary SHA-256 Merkle tree
    cem_engine.py         Cryptographic Execution Manifest
    audit_engine.py       ECDSA-P384 audit record sealing
    cert_engine.py        X.509 5-layer certificate hierarchy
    signature_chain.py    7-level Ed25519 signature chain
    peer_id_engine.py     HKDF hardware-derived Peer ID
    integrity_engine.py   Per-chunk and file-level hash verification
    tamper_engine.py      Adaptive Tamper Resistance Score (TRS)
    execution_analyzer.py Pre-execution static behavioral analysis
    reconnect_engine.py   Trust-preserving session resumption
    metadata_engine.py    19-field dual-signed metadata exchange
  network/
    server.py             asyncio TCP gateway server
    client.py             asyncio client agent
  cli.py                  click-based command-line interface

Security Notes

• Transport: ZTOP is designed to run inside a TLS 1.3 tunnel. The reference implementation uses plain TCP for development convenience. For production use, place behind a TLS terminator or enable TLS in the network layer.
• HMAC Keys: The current implementation does not perform a key exchange during the handshake. Both sides use an unshared key by default, so HMAC validation is not enforced. A full ECDH-based key exchange is planned for v1.1.
• Post-Quantum: Ed25519 and ECDSA-P384 are not quantum-resistant. Future versions will incorporate NIST-standardized post-quantum algorithms.

See SECURITY.md for the full threat model and responsible disclosure policy.

Running Tests

pip install -e ".[dev]"
pytest tests/ -v --tb=short

Building for PyPI

python -m build
twine check dist/*
twine upload dist/*

IETF Reference

This implementation targets draft-ztop-secdispatch-protocol-00, submitted to the IETF SECDISPATCH working group.

Internet-Draft: https://datatracker.ietf.org/drafts/current/

License

MIT — see LICENSE.