README

A Blockchain database suitable for both private or public blockchains.

Blocks are stored with transactions as JSON so they are very portable
Database has been designed to handle large amounts of Blocks and can be quickly synced across multiple servers (if required)
Transactions are encoded in a Merkle Tree, any attempt to change the transaction will be detected and duplicate transactions submitted in other blocks can also be detected.
Proof of work can be disabled for private blockchains to remove unnecessary and cumbersome calculations
It is very fast, you can search for the furthest away hash in the index of 2 million blocks in 0.44 seconds (2012 laptop)

Trying it out

I have included demo.php which will create a Blockchain with Blocks and Transactions

Clone the source code to a directory

$ git clone https://github.com/jamielsharief/blockchain blockchain-demo

Run composer install

$ cd blockchain-demo
$ composer install --no-dev

Then run the demo script

$ php demo.php

Create

To create a Blockchain instance, provide a path to where data for that Blockchain will be stored.

$blockchain = new Blockchain('customer-payments', __DIR__ . '/data/blockchains', [
    'difficulty' => 4, // set to 0 to disable proof of work
    'lookback' => 10, // number of Blocks to look back for duplicate transactions
    'version' => 1
]);

For a private Blockchain, set difficulty to 0, since no proof of work is required.

The Blockchain is created when you add the first Block of Transactions.

Create a Transaction object and pass the data to the constructor.

$transaction = new Transaction([
    'date' => '2020-10-27',
    'to' => 'Bob',
    'from' => 'Tony',
    'amount'=> 500
]);

Create a Block and add a Transaction to it, you can add as many Transactions as you need for each Block.

$block = new Block();
$block->add($transaction);

To add the Block to the Blockchain

$blockchain->insert($block);

Finding Blocks

To get a Block provide the block number

$block = $blockchain->get(4);
/*
{
    "hash": "0000a1b9dc3c28e3deacf1e862fd299fc7e29637da1c6c847e158141b8ac82cd",
    "version": 1,
    "previousHash": "000048cf5816b30cfb1b4fcf091fd801bd5ba9722a94fb42424df48a7d141fcc",
    "merkleRoot": "2924811dad7aebcc1772414d4296af5e21f636570c825dc8db22768660e92446",
    "timestamp": 1604053905,
    "difficulty": 4,
    "nonce": 116249,
    "index": 4,
    "noTransactions": 1,
    "transactions": [
        {
            "hash": "aa2c26771ca48904af0a5c2924ba8cebfd2bd37a6396a55db7d6939cb158a8dc",
            "data": {
                "date": "2020-10-30 22:31:45",
                "to": "2e6c1c401c5233c5b4e5f8b31938188f1375c4cc",
                "from": "f73c557f3c50b8be433a7a32dfcdd4d236e7ce23",
                "amount": 24087
            }
        }
    ]
}
*/

You can also search by hash

$block = $blockchain->find('0000d64537ceca1e65f5dca51bed677c6c6a5665b21725ef87dd6da21994e09c');

To get the most recent Block

$block = $blockchain->last(); // the last Block

Counting

To count the number of Blocks in the Blockchain

$blockchain->count();

List

To get a list of hashes of the most recent X Blocks with the Block number.

$list = $blockchain->list(); // defaults to 10
/*
Array
(
    [9] => 0000b08e7e34f3cafb35602123d3aa18416d2279d36ab702fa9feac8758f6f66
    [8] => 0000963bc54ec3dba730e186bbddd03bf754117057b6d534a4c08610052b5c12
    [7] => 0000e042bdd2208d8187d6166dfb2f4cc9851d8a256178460f9daab56224f9f2
    [6] => 00008e61f6338138705ad6a389e0149e872c60839c5a638efc5cc44953c3820e
    [5] => 00005d7994266b55b1c48ceb79f59bc5fe9d786ab672417a6abba2db3f47a558
    [4] => 0000807d375c5fbe63f13445cec81abaf132eec8fb0f04bf7de8a68c29d173eb
    [3] => 0000fb7f973b48a0a928f190c843820b4bb91ba305330f702035b8d4dc64003f
    [2] => 000043adb9258af0b5b564e96ca20ed6709e4b3ebb84498d1a334b5a185cd788
    [1] => 0000d14502ac90c9047f3f43c96678dc4329db98f9e94c775f72a27d54820e87
    [0] => 0000a543c66f641c0998711f71afe2393ec3ed1b6ecefe979873f1ae4e5c15d2
)
*/

To list a custom amount of Blocks

$list = $blockchain->list(10000);

All

To go through all Blocks in the Blockchain, use the all method which yeilds each Block so that it can be done in a memory efficient manner.

foreach($blockchain->all() as $block){
    $transactions = $block->transactions;
}

The following options can be used

start: default:0 from which block number
finish: default:[last block] to which block number
reverse: default: true. Goes through Blocks starting at the most recent block if set

Validating the Blockchain

On my 2012 Mac Book it took me approx 9 minutes to validate a Blockchain with 1.2 million Blocks and roughly 6 million Transactions.

To validate the entire Blockchain.

$blockchain->validate();

Todo

I am thinking the following:

If the first set of transactions should define the schema going forward of all future transactions.
maybe an encrypted Blockchain could be interesting for private Blockchains to protect data

jamielsharief / blockchain

Maintainers

Details