Secure store-and-forward files, mail, and commands

 NNCP is a package facilitating secure store-and-forward file and mail
 exchange. It can be thought of as a modern UUCP with Internet smarts.
 .
 NNCP supports direct online communication over a LAN or Internet,
 scheduled communication, offline copies, streaming communication
 (pipes), and more. It can therefore be used for air-gapped computers
 that might be communicated with by CD-ROM, tape, or USB stick. It can
 also be used for intermittent or on-demand links, very slow or high
 latency links, etc.
 .
 NNCP can build up ad-hoc friend-to-friend (F2F) statically routed,
 darknet, delay-tolerant networks for fire-and-forget secure reliable
 files, file requests, Internet mail and commands transmission. All
 packets are integrity checked, end-to-end encrypted, explicitly
 authenticated by known participants public keys. Onion encryption is
 applied to relayed packets. Each node acts both as a client and server, can
 use push and poll behaviour model. Also there is multicasting areas support.
 .
 Out-of-box offline sneakernet/floppynet, dead drops, sequential and append-only
 CD-ROM/tape storages, air-gapped computers support. But online TCP daemon with
 full-duplex resumable data transmission exists.