hush/vendor/google.golang.org/protobuf/proto/doc.go
jx12n 4d9a26498e hush: one-time secret links the server cannot read
Paste a secret, get a link, send it. The first person to open it and press
Reveal sees the secret; the link dies at that moment. The recipient needs a
browser and nothing else — no account, no client, no installed tooling.

The server cannot read what it stores. AES-256-GCM happens in the browser and
the key lives in the URL fragment, which browsers never transmit, so hushd
holds ciphertext and no key material. That is a property of where the key sits
rather than a promise about our conduct, which is why there is deliberately no
endpoint accepting a plaintext secret and no server-side-encryption fallback:
two guarantees behind one URL would be worse than one honest guarantee.

Three decisions carry the design:

  * GET /s/{id} touches NO storage, not even to check existence. Slack, Teams,
    WhatsApp, iMessage and Outlook Safe Links all fetch a URL before a human
    sees it, so destroying on GET would destroy most secrets in transit and the
    recipient's "already used" would be indistinguishable from interception.
    Only POST /reveal consumes. Bot user-agent detection is an arms race;
    removing the side effect from GET is not. Pinned by
    TestGettingTheRevealPageNeverConsumesTheSecret.
  * Destruction is one Redis GETDEL, which is atomic. GET-then-DEL has a window
    where two simultaneous readers both win, and for a one-time secret that
    window is the product. The store contract demands atomicity and the same
    concurrency test runs against both implementations.
  * Missing, already-revealed, expired and evicted are ONE indistinguishable
    410. Separating them would confirm to a prober that a given link was real.

The secret id IS the capability, so secret.ID is a struct whose every
accidental path — %v, %s, String(), slog, json.Marshal — emits a redacted
handle or refuses, and the raw value needs an explicit Value(). The first
version tried to prevent leaks by implementing no String() at all; its own test
caught that Go's fmt prints unexported fields anyway, so forbidding the method
had removed the control rather than the leak.

Operationally: structured JSON on stdout in the fleet's wire format, which
Vector already collects with no annotation; six hush_* metrics on the chassis
registry with no id, IP or path in any label; five alert rules wired into
vmalert. The public Ingress enumerates /, /s/ and /api/ so /metrics, /healthz
and /readyz share the port but are unreachable from the internet — no
basic-auth middleware to maintain and get wrong.

Dependencies are vendored because go-chassis is private: the Woodpecker test
step and the in-cluster Kaniko build both run -mod=vendor with GOPROXY=off and
hold no git credential.

cmd/hush-mcp is a stdio MCP server doing the same client-side crypto locally,
so using hush from an agent preserves the same guarantee as using it from a
browser.
2026-09-03 00:08:38 -06:00

87 lines
3.2 KiB
Go

// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package proto provides functions operating on protocol buffer messages.
//
// For documentation on protocol buffers in general, see:
// https://protobuf.dev.
//
// For a tutorial on using protocol buffers with Go, see:
// https://protobuf.dev/getting-started/gotutorial.
//
// For a guide to generated Go protocol buffer code, see:
// https://protobuf.dev/reference/go/go-generated.
//
// # Binary serialization
//
// This package contains functions to convert to and from the wire format,
// an efficient binary serialization of protocol buffers.
//
// - [Size] reports the size of a message in the wire format.
//
// - [Marshal] converts a message to the wire format.
// The [MarshalOptions] type provides more control over wire marshaling.
//
// - [Unmarshal] converts a message from the wire format.
// The [UnmarshalOptions] type provides more control over wire unmarshaling.
//
// # Basic message operations
//
// - [Clone] makes a deep copy of a message.
//
// - [Merge] merges the content of a message into another.
//
// - [Equal] compares two messages. For more control over comparisons
// and detailed reporting of differences, see package
// [google.golang.org/protobuf/testing/protocmp].
//
// - [Reset] clears the content of a message.
//
// - [CheckInitialized] reports whether all required fields in a message are set.
//
// # Optional scalar constructors
//
// The API for some generated messages represents optional scalar fields
// as pointers to a value. For example, an optional string field has the
// Go type *string.
//
// - [Bool], [Int32], [Int64], [Uint32], [Uint64], [Float32], [Float64], and [String]
// take a value and return a pointer to a new instance of it,
// to simplify construction of optional field values.
//
// Generated enum types usually have an Enum method which performs the
// same operation.
//
// Optional scalar fields are only supported in proto2.
//
// # Extension accessors
//
// - [HasExtension], [GetExtension], [SetExtension], and [ClearExtension]
// access extension field values in a protocol buffer message.
//
// Extension fields are only supported in proto2.
//
// # Related packages
//
// - Package [google.golang.org/protobuf/encoding/protojson] converts messages to
// and from JSON.
//
// - Package [google.golang.org/protobuf/encoding/prototext] converts messages to
// and from the text format.
//
// - Package [google.golang.org/protobuf/reflect/protoreflect] provides a
// reflection interface for protocol buffer data types.
//
// - Package [google.golang.org/protobuf/testing/protocmp] provides features
// to compare protocol buffer messages with the [github.com/google/go-cmp/cmp]
// package.
//
// - Package [google.golang.org/protobuf/types/dynamicpb] provides a dynamic
// message type, suitable for working with messages where the protocol buffer
// type is only known at runtime.
//
// This module contains additional packages for more specialized use cases.
// Consult the individual package documentation for details.
package proto