Files
vault/CLAUDE.md
T
Andy Dixon 5aa60d7bc7 Add vault locking and a cross-platform build script
Commands that change the vault hold an exclusive lock on DIR/.lock and
readers hold a shared one, taken after the passphrase prompt. A blocked
process says it is waiting. Unix uses fcntl locks and Windows uses
LockFileEx, both released by the OS if the process dies. Plan 9 and
WebAssembly fall back to an exclusive lock file.

build.sh cross-compiles static binaries for every Go target that builds
without cgo (43 today, armv6 and armv7 for 32-bit ARM Linux) and writes
SHA256SUMS.
2026-09-26 14:36:44 +01:00

2.4 KiB

CLAUDE.md

This file provides guidance to Claude Code when working with this repository.

Overview

vault is a post-quantum encrypted file vault: one package main at the repo root that builds a single vault binary. Module github.com/andydixon/vault.

  • main.go - CLI: genkey, init, add, list, get, mv, rm.
  • keyfile.go - key file with two passphrase slots (Argon2id + XChaCha20-Poly1305 sealing a suite ID and 32-byte master seed). The second slot is either a decoy identity or random bytes; slot order is random.
  • store.go - on-disk vault: records/ holds fixed-size encrypted catalogue records, objects/ holds padded encrypted file bodies. Records a key cannot open are skipped, not treated as errors.
  • lock*.go - vault lock on DIR/.lock: fcntl on unix, LockFileEx on Windows, an exclusive lock file elsewhere. Writers lock exclusively, readers shared, taken after the passphrase prompt.
  • build.sh - cross-compiles every go tool dist list target except iOS and android/386, amd64, arm (cgo-only).
  • internal/pqcrypt - file encryption (header + STREAM ChaCha20-Poly1305), suite registry, hybrid FrodoKEM-640 + ML-KEM-768 default suite.
  • internal/format, internal/stream, internal/term - header encoding, chunked payload encryption, terminal passphrase prompts.

Commands

go test ./...
go build .
./build.sh                                  # all platforms, into ./dist
TARGETS="linux/amd64" ./build.sh            # a subset

End-to-end check:

export VAULT_PASSPHRASE=test VAULT_KEY=$PWD/k VAULT_DIR=$PWD/s
./vault genkey && ./vault init && ./vault add README.md docs && ./vault list

Invariants

  • Never write a seed or private key unencrypted.
  • Keep suite IDs, stanza tags, HKDF info strings and fileKeySize (32) stable.
  • Every ciphertext's mtime is pinned to the epoch; records stay one fixed size; objects stay bucket-padded. These hide metadata from the storage host.
  • An object's plaintext starts with its own ID, binding it to its record.
  • get publishes output only after the entire object has authenticated.
  • Decoy deniability: both key slots stay the same size and are both always tried; init always writes filler; foreign records are skipped silently.
  • Every command that changes the vault holds the exclusive lock.
  • Keep dependencies pure Go and CGO_ENABLED=0 builds working.
  • Diagnostics go to standard error, lower-case, no trailing full stops.