DIVA Blockchain

A blockchain implementation using Practical Byzantine Fault Tolerance (PBFT) in combination with Proof-of-Stake (PoS) as a consensus algorithm. It is therefore a "Weighted Practical Byzantine Fault Tolerance" consensus.

This is a fully anonymous ("Privacy-By-Design"), very lightweight, fast, low-energy and permissionless blockchain.

The load of the PBFT consensus is network bound. The chain gets built by "communication" instead of "computation". Therefore many messages are crossing the network.

The peers in the network communicate over I2P. The peers build the tunnels between each other using a secure and efficient "Challenge/Auth" process based on regular asymmetric keys (public/private keys). "Sodium" gets used as the single crypto library - so all crypto-related code is based on solid, very well tested and proven code.

Architecture / Flow

The network itself is permission- and leaderless. Each peer in the network represents a round-based state machine. Each round produces a block. The blocks do have a variable size and blocks are produced on demand.

1. New proposal: each peer in the network may anytime propose a transaction, by sending it to the network. Per round, each peer can only add one own transaction.
2. Voting: each peer receiving a proposal may send a vote to the network. Such a vote represents an agreement of a peer with a specific stack of proposals. Each peer can vote only once. If the peers in the network do not agree (2/3 of the total stake of all peers) on a specific stack of proposals, the voting will go into a new round and all peers can vote again.
3. Creation of a new block: as soon as consensus is reached through voting for a specific stack of proposals, peers will create the new block.

API Overview

Divachain supports two API's: a) an HTTP REST API running by default on port 17468 b) a broadcasting websocket running by default on port 17468

In a nutshell: use the REST API to write transaction proposals to the chain or use the REST API to read status information from the chain. Use the websocket to get live updates.

Create Your Local Environment

To create a docker based local environment use the project https://codeberg.org/diva.exchange/diva-dockerized.

Configuration

The configuration can be controlled using environment variables.

NO_BOOTSTRAPPING

Set to 1 to skip bootstrapping.

Default: 0

BOOTSTRAP

URL to a entrypoint in the network, like http://diva.i2p.

Default: (empty)

IP

Default: 127.0.0.1

PORT

Default: 17468 REST API as documented below (API Endpoints).

BLOCK_FEED_PORT

Default: 17469 Websocket Feed, broadcasting block data to its listeners.

I2P_SOCKS_HOST

I2P_SOCKS_PORT

I2P_SAM_HTTP_HOST

I2P_SAM_HTTP_PORT_TCP

I2P_SAM_UDP_HOST

I2P_SAM_UDP_PORT_TCP

I2P_SAM_UDP_PORT_UDP

I2P_SAM_FORWARD_HTTP_HOST

I2P_SAM_FORWARD_HTTP_PORT

I2P_SAM_LISTEN_UDP_HOST

I2P_SAM_LISTEN_UDP_PORT

I2P_SAM_FORWARD_UDP_HOST

I2P_SAM_FORWARD_UDP_PORT

NETWORK_P2P_INTERVAL_MS

Interval, in milliseconds, to build and maintain the P2P the network (connect to peers, if needed).

Minimum: 10000
Maximum: 60000
Default: Minimum

NETWORK_CLEAN_INTERVAL_MS

Interval, in milliseconds, to clean up the network environment (like gossiping data).

Minimum: 30000
Maximum: 60000
Default: Minimum

NETWORK_SYNC_SIZE

Maximum number of blocks of synchronization message might contain. Must not exceed API_MAX_QUERY_SIZE.

Minimum: 10
Maximum: 100
Default: Minimum

BLOCKCHAIN_MAX_BLOCKS_IN_MEMORY

Number of blocks kept in memory (cache).

Minimum: 100
Maximum: 1000
Default: Maximum

API_MAX_QUERY_SIZE

Number of blocks which can be queried through the API.

Minimum: 10
Maximum: 100
Default: Maximum

API Endpoints

Quering the Blockchain

GET /about

Returns an object containing the version, the license and the public key of the peer.

GET /network/{stake?}

Returns the network participants. If stake is given and greater than zero, only network participants with a stake greater-or-equal than the given threshold will be returned.

GET /state/search/{search?}

Search states using a search string. If no search string is given, it returns the last API_MAX_QUERY_SIZE states.

Example: http://url-divachain-api/state/search/DivaExchange:OrderBook:BTC_ETH

Remark: Not more than API_MAX_QUERY_SIZE states can be requested at once.

GET /state/{key}

Get a specific state from the local state database. The local state database is a key/values storage and represents a well-defined set of current states.

Example: http://url-divachain-api/state/decision:DivaExchange:Auction:BTC_ETH

GET /stack

Get the stack (queue) of local transactions.

GET /pool/tx

Get the current transactions in the pool.

GET /pool/votes

Get the current votes in the pool.

GET /block/genesis

Get the genesis block.

GET /block/latest

Get the latest block on the chain.

GET /block/{height}

Get a specific block on the given height.

Example: http://url-divachain-api/block/10 will return the block on height 10.

Error handling: If a block is not yet available, 404 (Not Found) will be returned.

GET /blocks/{from?}/{to?}

Get all blocks between height "from" (inclusive) and height "to" (inclusive). If "to" is not yet available, the blocks until the current height will be returned.

Example: http://url-divachain-api/blocks/10/19/ will return 10 blocks (block 10 until 19, if all blocks are already available).

Example: http://url-divachain-api/blocks will return the latest API_MAX_QUERY_SIZE blocks (at most).

Error handling: 404 (Not Found) will be returned.

Remark: Not more than API_MAX_QUERY_SIZE blocks can be requested at once.

GET /blocks/page/{page}/{size?}

Get a specific page of the blockchain, starting at the current height (reverse order). If size is not given, it will return API_MAX_QUERY_SIZE blocks or less.

Example: http://url-divachain-api/blocks/page/1/5 will return the last 5 or less blocks of the chain.

Remark: Not more than API_MAX_QUERY_SIZE blocks can be requested at once.

GET /blocks/search/{search?}

Search blocks using a search string. If no search string is given, it returns the last API_MAX_QUERY_SIZE blocks.

Example: http://url-divachain-api/blocks/search/XMR will return the latest blocks containing the string XMR.

Remark: Not more than API_MAX_QUERY_SIZE blocks can be requested at once.

GET /transaction/{origin}/{ident}

Get a well-defined transaction.

Error handling: 404 (Not Found) will be returned if the transaction is not available.

Transmitting Transactions

PUT /transaction/{ident?}

Submit a new transaction proposal to the network. The body must contain an array of commands.

Example of such a transaction proposal, containing two commands:

[
  { seq: 1, command: 'data', ns: 'test:data', d: 'data-1' },
  { seq: 2, command: 'data', ns: 'test:data', d: 'data-2' },
]

Joining and Leaving the Network

GET /join/{http}/{udp}/{publicKey}

Internal: part of an automated process.

Request to join the network.

Send this GET request to any remote peer in the network which is online. This remote peer will later - in some seconds or even minutes - send back an independent GET request to the local /challenge/ endpoint.

GET /leave/{address}

Internal: part of an automated process.

TBD.

GET /challenge/{token}

Internal: part of an automated process.

Response will contain the signed token. Verify the response with the public key of the remote peer.

Network Synchronization

GET /sync/{height}

This endpoint is part of an automated process.

Get a well-defined number of blocks starting from {height} (including). See NETWORK_SYNC_SIZE.

How to Run Unit Tests

If a local I2P test environment is wanted, start the local testnet container:

docker-compose -f test/local-i2p-testnet.yml up -d

Unit tests can be executed using:

npm run test

Unit tests contain functional tests and will create some blocks within the local storage.

To stop the local I2P test environment (and purge all data):

docker-compose -f test/local-i2p-testnet.yml down --volumes

Linting

To lint the code, use

npm run lint

Contact the Developers

On DIVA.EXCHANGE you'll find various options to get in touch with the team.

Talk to us via Telegram https://t.me/diva_exchange_chat_de (English or German).

Donations

Your donation goes entirely to the project. Your donation makes the development of DIVA.EXCHANGE faster.

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License

AGPLv3