rust-blockchain

A very simple blockchain in Rust.

In progress

• multiple-nodes (synchronize chain from other nodes chains)

Table of content

• Dependencies
• Block structure
• Start nodes
  • Create many nodes
  • Start a node
  • Check node IP address
• Find peers
  • Manually add a peer
  • List peers
• Blocks
  • Add block
  • List blocks

Dependencies

• time: time routines, used to easily get the current UTC timestamp (for block creation),
• sha1: sha1 hashing routines, in order to hash the previous block of the current created one,
• bincode: serialization routines, used to serialize a block into raw binary (used for hashing),
• serde/serde_derive: serialization/deserialization routines, in order to make a block "serializable"
• termion: provides terminal graphical routines

Block structure

A block of the ledger contains the following fields:

• the timestamp of the block creation,
• the data of the block (signed integer in order to be similar to cryptocurrencies),
• the hash digest of the previous ledger block (empty string if the current block is the genesis one)
• the hash digest of the current ledger block (stored as a string, hexadecimal digest)

The previous and current hash digests are directly fields of the block. The timestamp and the data fields are part of a hashable content structure, itself a field of the block structure.

In fact, in order to keep things as simple as possible, only the timestamp and the data are hashed into previous and current.

The Block structure implements the Serialize trait. In order to keep everything simple, and in order to prevent custom serialization functions, the block structure only contains primitive types (i64, i32 and String) as they all already implement the trait.

Every block of the chain contains the hash of the previous block. This is exactly how "blockchain" maintains integrity (for instance, changing a block data from the middle of the chain would require to change all the blocks that come after).

Start nodes

This section explains how to use the blockchain.

Create many nodes

Blockchain usually works with multiple nodes. In order to create multiple nodes, you can simply git clone or copy the project at different location, rename the PROJECT environment variable from the Vagrantfile (for instance, rust_blockchain_0, rust_blockchain_1, rust_blockchain_2...), and execute vagrant up for each of these program.

(beware, do not copy the hidden directory .vagrant/)

Start a node

To start a node, simply build the container:

vagrant up

Connect using SSH to the container:

vagrant ssh

Start the service:

./target/release/rust-blockchain

Check node IP address

IP address is necessary when synchronizing the local blockchain of a node. In order to check the private IP address of a node within the Docker LAN, simply execute:

docker inspect rust_blockchain_dev

This is also possible to set the IP address of a node into the Vagrantfile:

config.vm.network "private_network", ip: "10.10.10.10"

Find peers

This section is about communication between nodes.

Manually add a peer

The easiest way to link nodes together is to manually register a peer locally. Simply add a peer with add_peer.

add_peer 172.0.0.10

List peers

list_peers

Blocks

This section is about chain blocks.

Add block

Add a block and broadcast it to every peer.

For example, to add a block with the data 20:

add_block 20

List blocks

List all the blocks of the local chain:

list_blocks