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docs/ARCHITECTURE.md records why internal/web.render replaces the chassis JSON-API policy with a per-response nonce policy, and the failure each of the three decisions prevents: a header-only policy because two policies on one response intersect, a nonce instead of 'unsafe-inline' because the guarantee is that only the reviewed same-document script reaches the fragment key, and a fresh url-alphabet value because a reused nonce is worth 'unsafe-inline' to anyone who waits for the next load and + or / would make enforcement depend on entity decoding. README.md now names the buttons the page actually renders and says outright that there is no lifetime picker — the server's 24h default applies and ttl_seconds is where a caller chooses. base.html drops the opacity transition; nothing animates opacity. .dockerignore is an allowlist, because the build stage COPYs only go.mod, go.sum, vendor/, cmd/ and internal/. A blocklist forgets the file nobody predicted, and for this service that file is a secret. .gitignore grows the same protection for the working tree.
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hush
Send someone a secret over a link that works once.
Production: https://hush.threesix.ai
Paste a secret, get a link, send the link. The first person to open it and press Reveal sees the secret; the link is dead from that moment. Nobody needs an account, a client, or anything installed — a browser is the whole requirement.
The server cannot read what you sent. Encryption happens in your browser and the
key lives in the URL fragment (…/s/ID#KEY), which browsers never transmit.
hush stores ciphertext it has no way to open. That is not a promise about our
operational discipline; it is a property of where the key sits.
What one-time actually buys you
Worth being precise, because "one-time link" is often oversold:
- Bounded exposure. The secret is fetchable once, for at most its TTL, then it is gone. A credential sitting in a Slack thread is fetchable forever by anyone who later gains access to that thread.
- Tamper evidence. If your recipient says "already used", someone else opened it. You have learned something a plain paste never tells you.
- Nothing at rest to steal. A dump of hush's Redis yields ciphertext and no keys.
And what it does not buy you:
- It does not protect the link. Whatever channel carries the link could be read by whoever can read that channel. One-time-ness limits the damage and makes it detectable; it does not make the channel private.
- It does not authenticate the reader. Anyone holding the link can open it. The link is the capability. Treat it like the secret it carries.
If a secret must reach one specific verified human and nobody else, this is the wrong tool — use a channel with identity.
Usage
In a browser
- Open https://hush.threesix.ai.
- Paste the secret, press create a secret.
- Copy the link and send it however you like.
- The recipient opens it, presses reveal the secret, and reads it once.
There is no lifetime picker: the page offers one action, and the server applies
its default TTL (24 hours). ttl_seconds on the API is where a caller that
cares chooses.
Why there is a button
Slack, Teams, WhatsApp, iMessage and Outlook Safe Links all fetch a URL to build
a preview before any human sees it. A service that destroys on GET therefore
destroys most secrets in transit, and the recipient's "already used" is
indistinguishable from a real interception.
So in hush, GET /s/{id} is a static page that touches no storage at all. Only
POST /s/{id}/reveal reads and destroys. Link previewers are harmless by
construction, not by user-agent guessing.
API
The API takes ciphertext. There is no endpoint that accepts a plaintext secret, because such an endpoint would make the server able to read secrets and the claim at the top of this file would become a matter of trust rather than arithmetic.
POST /api/secrets
{ "ciphertext": "<base64url AES-256-GCM, nonce prepended>", "ttl_seconds": 86400 }
→ 201 { "id": "…", "expires_at": "2026-09-04T…Z", "ttl_seconds": 86400 }
POST /api/secrets/{id}/reveal
→ 200 { "ciphertext": "…" } first caller only, secret destroyed
→ 410 { "error": { "code": "gone" } } every other case
410 gone is returned identically whether the id never existed, was already
revealed, or expired. Distinguishing those would confirm to an attacker that a
particular link once existed.
GET / serves the create page, GET /s/{id} the reveal page. /healthz,
/readyz and /metrics are served on the same port but are not routed by the
public ingress — they are reachable in-cluster only.
From an agent, over MCP
cmd/hush-mcp is a stdio MCP server exposing two tools, hush_create and
hush_reveal. It runs locally and does the encryption on your machine, so
using hush from an agent preserves the same zero-knowledge property as using it
from a browser. See docs/MCP.md.
Limits
| Thing | Value | Why |
|---|---|---|
| Ciphertext | ≤ 64 KiB | It is a courier for credentials, not a file host |
| TTL | 5m … 7d, default 24h | Long enough to be useful, short enough to bound exposure |
| Rate limit | 30 creates / 10 min / IP | Anonymous create is otherwise a free blob host |
| Reveals per secret | exactly 1 | The product |
Operating it
- docs/ARCHITECTURE.md — how it works and why each choice
- docs/DEPLOY.md — pipeline, DNS, credentials, first deploy
- docs/OPERATIONS.md — alert runbook, log queries, failure modes
- docs/MCP.md — the MCP server and how to install it
Development
make help # every target
make release # build this commit in-cluster and roll it out, then smoke it
make test # unit tests, no external dependencies
make dev # a local Redis in Docker + hushd on :18500
make smoke # full create → reveal → gone against the local instance
make vendor # refresh vendor/ after a dependency change
go-chassis is a private module, so dependencies are vendored and both CI
and the container build run with -mod=vendor and no network. make vendor is
the only way dependency versions change.