https://github.com/haukened/quicshell
a next-generation post-quantum secure remote shell protocol over QUIC
https://github.com/haukened/quicshell
post-quantum post-quantum-cryptography quic quicshell remote-shell shell ssh
Last synced: 19 days ago
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a next-generation post-quantum secure remote shell protocol over QUIC
- Host: GitHub
- URL: https://github.com/haukened/quicshell
- Owner: haukened
- License: mit
- Created: 2025-09-06T20:00:42.000Z (28 days ago)
- Default Branch: main
- Last Pushed: 2025-09-13T21:18:14.000Z (21 days ago)
- Last Synced: 2025-09-14T04:19:47.657Z (21 days ago)
- Topics: post-quantum, post-quantum-cryptography, quic, quicshell, remote-shell, shell, ssh
- Language: Rust
- Homepage:
- Size: 163 KB
- Stars: 1
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
- Roadmap: roadmap.sh
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# QuicShell (qsh)
qsh is a modern secure remote shell, designed as a clean successor to SSHv2. The project is in the design & early implementation phase; this README is intentionally minimal and aimed at future users (not contributors).
## Why rethink SSH?
SSHv2 has served for decades, but several structural issues are hard to fix in-place:
1. Algorithm negotiation complexity creates downgrade / configuration risk.
2. One set of session keys stretches across all channels with infrequent rekeys.
3. TCP-only transport suffers head‑of‑line blocking and brittle network migration.
4. Ad‑hoc binary framing and sprawling extensions raise parsing & audit complexity.
5. Host key rotation is awkward; users either click through or get locked out.
6. Privacy signals (capability ordering, message sizing) are inconsistent.
7. Post‑quantum readiness requires bolt‑on patches instead of a coherent design.
## How qsh addresses this
qsh keeps the familiar user model (keys, TOFU, `qsh user@host`) while changing foundations:
* Fixed, modern hybrid cryptography (post‑quantum + classical) — no cipher negotiation.
* QUIC‑first transport with seamless TCP fallback for blocked UDP environments.
* Independent, frequently refreshed per‑channel (per direction) keys to narrow exposure windows.
* Deterministic, compact CBOR control messages for easier auditing and fuzzing.
* Explicit, signed host key rotation (“TOFU‑plus”) instead of silent trust shifts.
* Built‑in privacy measures (adaptive padding, canonical capability ordering).
* Versioned evolution (new ALPN for future modes) instead of in‑band option sprawl.
## Comparison
| Aspect | SSHv2 (today) | qsh v1 |
|--------|---------------|--------|
| **Crypto** | RSA / Ed25519 / Curve25519 (classical only) | **Hybrid post-quantum by default** (X25519 + ML-KEM-768, Ed25519 + ML-DSA-44) |
| **Key lifecycle** | One session key for all channels, rekey ~1GB/hour | **Per-channel, per-direction keys**; automatic rekey ≤1 MiB or 30 s (whichever first) |
| **Handshake** | Multi-roundtrip `KEXINIT`, cipher negotiation, downgrade risks | **Single 1-RTT handshake**, fixed suite (no negotiation) |
| **Transport** | TCP only → head-of-line blocking, fragile across NAT/Wi-Fi hops | **QUIC/UDP preferred** (multiplexing, migration, congestion control), **TCP fallback** |
| **Wire format** | Custom ad-hoc binary blobs, extension hell | **Deterministic CBOR maps**, simple, fuzzable, extensible |
| **Host trust** | TOFU `known_hosts`, awkward rotation | **TOFU-plus** (pinned hybrid keys, explicit signed rotations) |
| **Audit posture** | Optional session logging, weak tamper evidence | Planned option: **per-channel MAC chaining** (tamper-evident logs) |
| **Legacy behavior** | SSH to non-SSH service = confusing hangs | **Preface “QSH1” → fast fail** (“protocol mismatch”), predictable |
**Bottom line:**
- For the user: looks and feels like SSH.
- For the implementer/admin: a simpler spec, smaller attack surface, future-proof crypto, and better transport resilience.
## Current status
Planning & specification work are active. The reference implementation is **not yet ready for production use**. Interfaces and on‑disk formats may still change.
If you need a stable tool today: keep using SSH. Monitor this project if you care about a QUIC‑native, post‑quantum‑ready successor with a smaller, stricter spec.
## When might you switch later?
* You want lower latency interactive shells over variable networks.
* You need forward secrecy windows measured in seconds/megabytes, not hours/gigabytes.
* You operate in environments planning for post‑quantum migration.
* You prefer fixed suites (no negotiation spreadsheets) and simpler compliance narratives.
## Where are the details?
Deep technical definitions (message formats, key schedule, limits, staging) live in [`spec.md`](./docs/spec.md) and [`roadmap.md`](./docs/roadmap.md). This README intentionally defers those so it stays approachable.
## License
MIT — see `LICENSE`.
## Author
Created by @haukened (David Haukeness).
Project home: https://github.com/haukened/quicshell