CipherHorizon

Quick start · What it does · Features · How it compares · Methodology · Downloads

Post-quantum readiness for the protocols your organisation runs on: TLS, SSH and, next, VPN. A deep scan of each, a readiness level from L0 to L4, and one CycloneDX CBOM, self-hosted. By Offset Security.

Note

Pre-release (0.x). It works and is tested against real servers, but options and the API may still change before 1.0 (release checklist).

Recorded traffic is protected today only if the key exchange was post-quantum: NIST IR 8547 deprecates the quantum-vulnerable algorithms after 2030 and disallows them after 2035, and anything harvested before then can be decrypted later. CipherHorizon tells you which of your TLS endpoints and SSH servers are exposed, which machines carry quantum-vulnerable cryptography, and what to fix first. It runs on your network and sends nothing anywhere.

Quick start

Pick one, then open http://127.0.0.1:8080, type an address and press Enter.

Docker or Podman

docker run -d --name cipherhorizon -p 127.0.0.1:8080:8080 -v cipherhorizon-data:/data ghcr.io/offsetsecurity/cipherhorizon:0.8.0

Debian, Ubuntu, with the .deb from the Releases page (on RHEL or Fedora: sudo dnf install ./cipherhorizon-<version>-1.x86_64.rpm)

sudo apt install ./cipherhorizon_<version>_amd64.deb

Windows, with the zip from the Releases page, in a terminal run as administrator: a service that starts at boot

cipherhorizon.exe service install

Any OS (Linux, macOS, Windows; amd64 and arm64), from the release archive, running in this terminal

cipherhorizon serve

Sign-in is off until you want it: turn it on in Settings to give a team accounts and roles, or start with --sign-in on. Another port: cipherhorizon serve --port 9000 or CIPHERHORIZON_PORT=9000. Each OS, where the data lives, backup, upgrade and removal: docs/engineering/INSTALL.md.

From the command line, no server needed:

cipherhorizon tls scan example.com                     # the verdict: readiness, TLS hygiene score, what to fix
cipherhorizon tls scan smtp://mail.example.com         # STARTTLS: SMTP, IMAP, POP3, FTP, XMPP, LDAP, PostgreSQL
cipherhorizon tls scan --fail-on 'level<L3' api.example.com   # exit 3 when it fails: a CI gate
cipherhorizon ssh scan bastion.example.com              # readiness, the SSH baseline, the sshd_config lines to meet it
cipherhorizon ssh scan --fail-on baseline git.example.com      # exit 3 when the server does not meet the baseline
cipherhorizon tls scan --fail-on standard=nist-sp800-52r2 www.example.gov   # exit 3 when a published standard is not met

Scan only systems you own or are authorised to test.

What it does

1. Says where each endpoint stands on post-quantum

One question across everything: is recorded traffic exposed to harvest-now-decrypt-later? Every TLS endpoint and SSH server gets a level from L0 (the protocol in use cannot carry a post-quantum key exchange) to L4 (post-quantum key exchange and authentication), each protocol by its own stated rules. Systems are ranked for migration by exposure and by how long their data must stay secret.

2. Scans TLS and SSH in depth, and shows its work

The TLS scanner is its own wire implementation: every protocol from SSLv2 to TLS 1.3, every cipher suite and key-exchange group (X25519MLKEM768 included), the signature schemes (ML-DSA included), and the certificate chain against the Mozilla and Chrome root stores. Each of its checks says what it found, why it matters, what to do and its source; the TLS hygiene score (0 to 100) shows its arithmetic. The SSH auditor negotiates as OpenSSH 10.6 would, verifies every host key, never logs in, and writes the sshd_config lines that meet a cited baseline. What it cannot know, it reports as unknown instead of guessing.

A TLS endpoint: where it stands, then what to fix first	STARTTLS services, the same depth
SSH servers: readiness and the baseline, never a score	An SSH server: what a current client gets, every method in bits

3. Inventories machines, and hands over one CBOM

Two readable scripts (PowerShell and shell) inventory a machine without installing anything and without reading key material. TLS endpoints, SSH servers, machines and CBOMs imported from other tools merge into one CycloneDX 1.7 CBOM, with PDF reports and the OMB M-23-02 items per system.

A machine: platform state, coverage, algorithms and services	The inventory: everything seen, and what to replace first

What is in it

TLS endpoints	SSLv2 to TLS 1.3, every suite and group, signature schemes, the chain against the Mozilla and Chrome root stores or your own CA, OCSP stapling, CRLs, Certificate Transparency, HSTS, DH primes tested, session resumption and 0-RTT, weak-key tests on every served key. STARTTLS for 7 protocols. Over 60 cited checks.
SSH servers	Algorithm lists, negotiation as OpenSSH 10.6 would, every host key verified (ML-DSA and the composite ssh-mldsa44-ed25519 included), 23 cited checks, and the CipherHorizon SSH baseline 2026 with the sshd_config lines to meet it.
Post-quantum readiness	L0 to L4 for every TLS endpoint and SSH server, with harvest-now-decrypt-later exposure.
Classical strength	Every algorithm, key and cipher suite in bits, by NIST's methods. A suite is as strong as its weakest part, and names it.
Published standards	Each scan judged clause by clause against RFC 9325, NIST SP 800-52 Rev. 2, BSI TR-02102-2 and -4, the ANSSI TLS guide, Mozilla Modern and Intermediate, PCI DSS v4.0.1 and CNSA 2.0 (docs/standards.md).
Client simulation	What two dozen named clients, from current Chrome to Java 6 and IE 8, would negotiate with each TLS endpoint, or why they cannot connect (docs/clients.md).
Certificates	Any certificate in a chain as the whole X.509 document: validity, key and signature strength, every extension decoded, the PEM to copy.
Machines	Platform state (FIPS, TPM, disk encryption, Secure Boot), what OpenSSL and OpenSSH can do, TLS, SSH, VPN and authentication settings, certificates and which provider holds each key, and every listening service with the libraries it loaded.
Inventory	Everything merged into one CycloneDX 1.7 (or 1.6) CBOM: algorithms with their OIDs, certificates with serial and fingerprint. Every chart opens what it counts.
Findings and systems	Findings grouped by problem, with triage; systems ranked for migration; OMB M-23-02 export per system.
Reports	PDF per TLS endpoint, per SSH server and for the whole inventory; CycloneDX, CSV and JSON downloads.
Over time	Schedules, history, and what changed between two scans.
For teams	Sign-in when you want it: administrator, analyst and viewer roles, an exportable activity log.
For pipelines	tls scan and ssh scan with --fail-on gates (exit 3), JSON and CBOM output, and the REST API (/api/v1/openapi.json).
For assistants	An MCP server (cipherhorizon mcp, or /mcp on the web server): scan from Claude, Cursor or VS Code, ask about the fleet, quote the standard behind a finding; scope, read-only and role controls.

How it compares

	CipherHorizon	testssl.sh, SSLyze	SSL Labs	ssh-audit	New PQC CLIs
Form	Self-hosted web app and CLI	CLI	Public web service	CLI	CLI
Protocols	TLS (with STARTTLS) and SSH	TLS	Public HTTPS	SSH	Varies
Internal endpoints	Yes	Yes	No	Yes	Yes
History, schedules, accounts and roles	Yes	No	No	No	No
A post-quantum readiness level per endpoint	L0 to L4, with HNDL exposure	Lists groups	No	Flags classical key exchange	Varies
SSH judged against a policy	A cited baseline, and the sshd_config lines to meet it	No	No	Built-in and custom policies	Rarely
SSH client audit	No	No	No	Yes	No
STARTTLS	7 protocols	Yes	No	No	Rarely
Machine inventory and one CBOM	Yes	No	No	No	Some
Active probes (Heartbleed, ROBOT; DHEat for SSH)	No, by design: it sends no exploit or stress traffic	Yes	Yes	DHEat	No
Rating	TLS: its own hygiene score, arithmetic shown. SSH: meets the baseline or not	Letter grade	Letter grade	Pass, warn or fail per algorithm	Own scores

Use testssl.sh when you need active vulnerability probes on one host, and ssh-audit to audit SSH clients or stress a server's Diffie-Hellman. Use CipherHorizon when you need to know where your estate stands on post-quantum across protocols, keep track of it, and show the evidence.

Standards

NIST IR 8547 (transition timeline) · FIPS 203 ML-KEM · FIPS 204 ML-DSA · FIPS 205 SLH-DSA · RFC 8446 and RFC 9325 (TLS) · RFC 4253, RFC 9142 and RFC 10042 (SSH) · CycloneDX 1.6 and 1.7 (CBOM) · OMB M-23-02 (export structure). The readiness level, the TLS hygiene score and the SSH baseline are this project's own; how each is worked out is in docs/methodology.md.

Security and trust

• Self-hosted and offline. One static binary with the interface inside; no telemetry, no external requests but the scans you start. A scan contacts only its target.
• It passes its own scan. Served over HTTPS, it speaks TLS 1.2 (forward-secret AEAD only) and TLS 1.3 with the hybrid post-quantum key exchange, sends HSTS, and the test suite scans it with its own scanner.
• Accounts when you want them. Administrator, analyst and viewer roles, PBKDF2 password hashes, sessions that end, lock-outs, and an activity log an administrator can export. A server on the network will not start open unless told to (--open-network).
• Limits you set. --scan-allow restricts what can be scanned; loopback, link-local and cloud-metadata addresses are refused by default.
• Inventory scripts you can read. They install nothing, read no key material, and can only run the queries the script itself defines; cipherhorizon scripts list prints their hashes.
• Verifiable releases. Signed checksums (Sigstore), an SBOM per archive and build provenance.

Report vulnerabilities privately: SECURITY.md.

Documentation

docs/engineering/INSTALL.md	Installing on each OS, the port, where the data lives, backup, upgrade, removal
docs/deploy.md	Docker, Caddy with automatic HTTPS, systemd, Windows, backups
docs/CI.md	tls scan and ssh scan --fail-on, and a GitHub Actions example
docs/mcp.md	Using CipherHorizon from an assistant (Model Context Protocol): the tools, the safety controls, client setup
docs/methodology.md	Every check, the readiness levels, the TLS hygiene score, the SSH baseline
docs/tls-scanning.md	How the TLS scanner works and what it sends
docs/ssh-scanning.md	How the SSH auditor works, what it sends, and the SSH baseline
docs/standards.md, docs/clients.md	The published standards, clause by clause; the simulated clients and their sources
docs/estate-guide.md	Systems, machines, migration order
docs/importing.md, docs/exporting.md	CBOM in and out, OMB M-23-02
docs/cbom-model.md	What a CipherHorizon CBOM contains, and which parts are CycloneDX
docs/reference-data.md	The root stores and other dated lists compiled into the binary
docs/architecture.md	How it is built
/api/v1/openapi.json on a running server	The API

Try it without touching anyone else's systems

go run ./cmd/demo-targets                    # servers of known posture on 127.0.0.1:9440 and up
cipherhorizon serve --allow-loopback         # loopback scans are refused unless you say so

demo-targets prints what each server is and what to expect: a hybrid post-quantum server (L3), classical TLS 1.3 (L1), TLS 1.2 only (L0), a deliberately terrible SSLv3 server, a slow one, a private CA chain, one STARTTLS service per protocol, and SSH servers from an SSH-1 banner (L0) to an ML-DSA host key (L4), one of them hardened to meet the baseline. The screenshots on this page are these servers.

Building and testing

Go 1.27 or newer; no C compiler, no Node, no database server.

go build -o cipherhorizon ./cmd/cipherhorizon
go test ./...                       # unit and integration tests, including the UI and design rules
golangci-lint run ./...
bash testing/deploy/smoke.sh        # the container, as docker-compose.yml runs it
node testing/e2e/journey.mjs        # the browser journey, see testing/README.md

The interface is plain HTML, CSS and JavaScript modules embedded with go:embed; storage is SQLite through a pure-Go driver; the TLS scanner and the SSH auditor are their own wire implementations (internal/tlsprobe, internal/sshprobe). The design rules are in DESIGN.md.

Contributing

Bug reports, corrections to a finding or a citation, and pull requests are welcome: see CONTRIBUTING.md for the setup, conventions and the evidence rule every finding follows. Everyone participating follows the Code of Conduct.

License and credits

Apache 2.0. Made by Offset Security, whose post-quantum readiness practice helps teams plan the move. Fonts: Geist and Geist Mono (Vercel) and Newsreader, all under the SIL Open Font License.