Prailude, a full Nano Currency node and wallet

Overview

Prailude is an independent implementation of the Nano node that will be 100% compatible with the Nano network. It will have complete feature parity with the official node, as well as extra features and optimizations, and could serve as a testbed for Nano development in the future.

This is a feverish work in progress. Stay tuned.

Contributions of encouragement welcome. xrb_1f3ta53d59z8x9ixooz1ypzcparkboq935a67war46qcqinre9wb3sujnecj

Progress

There's still a lot of work to do, but much has also been completed. BONUS labels denote features not found in the core node.

• Node
  • Data storage - DONE
    I've chosen to use Sqlite3 as the data store. The db logic is entirely encapsulated and can be swapped for something more performant later if necessary.
  • Crypto - DONE
    All crypto primitives are implemented. The most efficient implementation of ed25519 -- Ed25519-donna is used.
    • BONUS Batch signature verification - DONE
      Ed25519 has the peculiar property that it is more efficient to verify several signatures at once than one at a time. In my benchmarks, this offers a 40-70% decrease in CPU cycles used for sig checking. Considering sig checking is the most CPU-hungry task save for generating PoW, this is pretty good.
  • Protocol
    • Parsing - 95%
      Everything except generating bulk_pull and frontier_req responses is finished. Parsing of all incoming network data is complete.
  • Network
    • Peer Discovery - DONE
      Keepalives are sent and processed as needed
    • Bootstrapping
      • Frontier fetch - DONE
        Frontiers are fetched from several peers in parallel, with detailed progress reports. Frontiers that are too small are detected in the first second of data transfer and aborted to move on to better peers.
      • Account pulls - DONE
        Frontiers get loaded from the faster peers in parallel, and peers failing to respond with useful data are de-prioritized.
      • Fork resultion - TODO
        Forks encountered during bootstrapping need to be resolved before proceeding. There are several heuristics available to do this, as well as using confirm_reqs to resolve specific blocks when the heuristics fail. This is one of the most complex parts of the Nano protocol.
      • Block verification - 60%
        Once loaded, blocks must be verified and stored in the database. Any issues here must be resolved before considering the node as synced.
      • Process pending-blocks backlog - TODO
        While we were bootstrapping, a whole bunch of blocks make their wait to us on the network.
    • Block handling - TODO
      Incoming blocks must be verified for proof-of-work, associated with the owner's account, signature-checked, and verified that its data (like balance) is consistent. Afterwards, votes for the block must be tallied until quorum is reached. All newly seen (and valid) blocks must be rebroadcast to at least some peers.
    • Vote handling - 30%
      Votes must be validated ( DONE ), associated with pending blocks, and tallied. Votes on forking blocks must be respected.
    • Serving as a representative - TODO
      As a voting representative, the node must vote on incoming blocks, handle fork elections and respect their results.
    • Publishing blocks - 50%
      In response to user input, the node must publish transactions onto the network.
    • BONUS Node reputation tracking - 30%
      remember which nodes were helpful during bootstrapping, which ones were out of sync, too slow, or outright malicious. Which ones publish invalid blocks or votes. Treat them accordingly.
  • Wallet
    • Seeding - TODO
      Accounts must be generated from a seed, which can be backed up and restored. The backup should be compatible with the core node's format.
    • Balance tracking - 40%
      Balances must be kept up-to-date and xrb/raw units must be respected.
    • BONUS Account groups
      several accounts can be grouped together to form a single usable entity tracking its balance and using the sub-accounts as needed for transactions
  • Interface
    • RPC - TODO
      Feature-complete RPC interface with parity to core node, and then some.
    • Websocket - TODO
      Enables realtime tracking of data.
    • GUI Wallet
      Write an Electron app (sorry, i know it's a bloat, but I don't have time to learn Qt) or use Canoe.
  • BONUS Named Accounts
    Unique, decentralized, distributed account naming system, built by thoroughly reusing the Nano protocol with a slightly different DAG validation scheme. I've already worked out most of the details, and this is readily possible. In order for this system to go live, however, most representatives would need to run a supporting rep node.