A VSP running vspd can be used to vote on any ticket - tickets do not need to be purchased with any special conditions such as dedicated outputs for paying VSP fees. Fees are paid directly to the VSP with an independent on-chain transaction.

To use vspd, ticket holders must prove ownership of their ticket with a cryptographic signature, pay the fee requested by the VSP, and submit a private key which enables the VSP to vote the ticket. Once this process is complete the VSP will add the ticket to a pool of always-online voting wallets.

Features

API - Tickets are registered with the VSP using a JSON HTTP API. For more detail on the API and its usage, read api.md
Web front-end - A minimal, static, website providing pool stats.
Two-way accountability - All vspd requests must be signed with a private key corresponding to the relevant ticket, and all vspd responses are signed by with a private key known only by the server. This enables both the client and the server to prove to outside observers if their counterparty is misbehaving. For more detail, and examples, read two-way-accountability.md.
Dynamic fees - Clients must request a new fee address and amount for every ticket. When these are given to a client, there is an associated expiry period. If the fee is not paid in this period, the client must request a new fee. This enables the VSP admin to change their fee as often as they like.

Implementation

vspd is built and tested on go 1.13 and 1.14, making use of the following libraries:

gin-gonic/gin webserver.
etcd-io/bbolt k/v database.
jrick/wsrpc for RPC communication with dcrd and dcrwallet.

Deployment

Single server running vspd and dcrd. dcrd on this server is used for fishing ticket details out of the chain, and for broadcasting and checking the status of fee transactions. --txindex is required so getrawtransaction can be used.
A xpub key is provided to vspd via config. vspd will use this key to derive a new addresses for each fee payments. It is recommended to export an xpub from a cold wallet which is not a part of the vspd deployment.
Multiple remote voting servers, each running dcrwallet and dcrd. dcrwallet on these servers should be constantly unlocked and have voting enabled. Three voting servers in different physical locations are recommended for production.

Backup

The bbolt database file used by vspd is stored in the process home directory, at the path {homedir}/data/{network}/vspd.db. vspd keeps a file lock on this file, so it cannot be opened by any other processes while vspd is running.

To facilitate back-ups, vspd will write periodically write a copy of the bbolt database to the path {homedir}/data/{network}/vspd.db-backup. A copy of the database file will also be written to this path when vspd shuts down.

Issue Tracker

The integrated github issue tracker is used for this project.

License

vspd is licensed under the copyfree ISC License.