Files
meshcore-analyzer/cmd/decrypt/go.mod
Kpa-clawbot c233c14156 feat: CLI tool to decrypt and export hashtag channel messages (#724)
## Summary

Adds `corescope-decrypt` — a standalone CLI tool that decrypts and
exports MeshCore hashtag channel messages from a CoreScope SQLite
database.

### What it does

MeshCore hashtag channels use symmetric encryption with keys derived
from the channel name. The CoreScope ingestor stores **all** GRP_TXT
packets, even those it can't decrypt. This tool enables retroactive
decryption — decrypt historical messages for any channel whose name you
learn after the fact.

### Architecture

- **`internal/channel/`** — Shared crypto package extracted from
ingestor logic:
  - `DeriveKey()` — `SHA-256("#name")[:16]`
  - `ChannelHash()` — 1-byte packet filter (`SHA-256(key)[0]`)
  - `Decrypt()` — HMAC-SHA256 MAC verify + AES-128-ECB
  - `ParsePlaintext()` — timestamp + flags + "sender: message" parsing

- **`cmd/decrypt/`** — CLI binary with three output formats:
  - `--format json` — Full metadata (observers, path, raw hex)
  - `--format html` — Self-contained interactive viewer with search/sort
  - `--format irc` (or `log`) — Plain-text IRC-style log, greppable

### Usage

```bash
# JSON export
corescope-decrypt --channel "#wardriving" --db meshcore.db

# Interactive HTML viewer
corescope-decrypt --channel wardriving --db meshcore.db --format html --output wardriving.html

# Greppable log
corescope-decrypt --channel "#wardriving" --db meshcore.db --format irc | grep "KE6QR"

# From Docker
docker exec corescope-prod /app/corescope-decrypt --channel "#wardriving" --db /app/data/meshcore.db
```

### Build & deployment

- Statically linked (`CGO_ENABLED=0`) — zero dependencies
- Added to Dockerfile (available at `/app/corescope-decrypt` in
container)
- CI: builds and tests in go-test job
- CI: attaches linux/amd64 and linux/arm64 binaries to GitHub Releases
on tags

### Testing

- `internal/channel/` — 9 tests: key derivation, encrypt/decrypt
round-trip, MAC rejection, wrong-channel rejection, plaintext parsing
- `cmd/decrypt/` — 7 tests: payload extraction, channel hash
consistency, all 3 output formats, JSON parseability, fixture DB
integration
- Verified against real fixture DB: successfully decrypts 17
`#wardriving` messages

### Limitations

- Hashtag channels only (name-derived keys). Custom PSK channels not
supported.
- No DM decryption (asymmetric, per-peer keys).
- Read-only database access.

Fixes #723

---------

Co-authored-by: you <you@example.com>
2026-04-12 22:07:41 -07:00

23 lines
645 B
Modula-2

module github.com/corescope/decrypt
go 1.22
require (
github.com/meshcore-analyzer/channel v0.0.0
modernc.org/sqlite v1.34.5
)
require (
github.com/dustin/go-humanize v1.0.1 // indirect
github.com/google/uuid v1.6.0 // indirect
github.com/mattn/go-isatty v0.0.20 // indirect
github.com/ncruces/go-strftime v0.1.9 // indirect
github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
golang.org/x/sys v0.22.0 // indirect
modernc.org/libc v1.55.3 // indirect
modernc.org/mathutil v1.6.0 // indirect
modernc.org/memory v1.8.0 // indirect
)
replace github.com/meshcore-analyzer/channel => ../../internal/channel