Skip to content
deaddrop

Architecture

deaddrop has two halves, both in one binary:

  • deaddrop serve runs on a machine with a good connection. It leeches the torrent, encrypts it and serves the ciphertext over iroh.
  • deaddrop fetch runs wherever you want the files. It downloads, verifies and decrypts.

The life of a drop

Section titled “The life of a drop”

  1. Leech. librqbit, built with disable-upload, downloads the torrent. There is no incoming BitTorrent listener. See No seeding.

  2. Tear down the swarm. The torrent is removed from the session and the session (DHT, trackers, peer connections) is stopped before iroh starts serving.

  3. Seal. A new X25519 age key is generated in memory. Each file is encrypted to it and the plaintext is deleted as soon as it’s encrypted. Real names go into an encrypted manifest, deaddrop-manifest.age. See Encryption.

  4. Publish. The encrypted files are imported into an iroh-blobs store by reference (not copied) and grouped into one collection: the encrypted manifest first, then the files, named by index only (0, 1, 2…). The server only answers get requests for that collection. The server prints a ticket: the collection hash plus the server’s iroh endpoint address.

  5. Transfer. The client dials the endpoint from the ticket. iroh tries a direct QUIC connection with NAT hole punching and falls back to a relay, so neither side needs an open port. Every chunk is verified against its BLAKE3 hash as it arrives.

  6. Open. The client decrypts the manifest, then each file, and writes them under their real names. Wrong key or tampered data is an error.

  7. Vanish. A single-use server shuts down (or, with --wait-for-reset, deletes the data and waits). A temp data directory is deleted on exit.

Protocols on the endpoint

Section titled “Protocols on the endpoint”
ALPN Purpose Enabled
iroh-blobs Serves the encrypted collection Always
deaddrop/reset/0 Accepts deaddrop reset requests Only when a reset token is set

Source layout

Section titled “Source layout”

For contributors, the source is small:

File Role
cli.rs Command-line definition and help text
config.rs TOML config loading and precedence
torrent.rs Leech-only BitTorrent download via librqbit
crypt.rs age encryption, the manifest, decryption
server.rs serve: blob store, iroh router, single-use lifecycle
gate.rs Decides which blob requests are answered: only get for the current collection, one client at a time in single use
reset.rs The deaddrop/reset/0 protocol, server and client side
client.rs fetch: download, verify, decrypt
notify/ Discord and webhook notifiers