neilmehta31 / blockchain-csf425

Assignment for the course BITS-F452 Blockchain under Prof. Dr. Geetha Kumari

How to run:

First we need to make a virtual environment:

$ virtualenv venv

Then we activate the virtual environment:

$ source venv/bin/activate

(if on linux or mac) OR

$ ./venv/Scripts/activate

(if on windows)

We install the required dependencies for this project:

$ pip install -r /requirements.txt

Run the following command to get the Flask API started to get the endpoints to the Blockchain Network:

python3 main.py

The following command will run the main.py file on your localhost at the port 8000. On your browser open the link http://localhost:8000/<endpoints>.

You are all set to view the blockchain and use it.

The endpoints and their functionalities are listed below :

GET endpoints:

/chain: displays info about the whole chain

/mine: to add all the left transactions to the block and add it to the block

/time: to display the time of each transaction

POST endpoints:

/new_transaction: to add a new transaction to the pool

/add_block: to add a whole new block to the blockchain (multiple transactions in a block)

/register_node: to register a node to the network

/register_with: to register and sync a new node to the network

The blockchain has the following format:

{
    "length": 3,
    "chain": [
        {
            "index": 0,
            "transactions": [],
            "timestamp": 0,
            "previous_hash": "0",
            "nonce": 0,
            "hash": "6dbf23122cb5046cc5c0c1b245c75f8e43c59ca8ffeac292715e5078e631d0c9"
        },
        {
            "index": 1,
            "transactions": [
                {
                    "Customer": "neil",
                    "Amount": "150",
                    "Drink": "Irish Frappe",
                    "timestamp": "Sat Sep 25 21:38:10 2021"
                }
            ],
            "timestamp": "Sat Sep 25 21:38:15 2021",
            "previous_hash": "6dbf23122cb5046cc5c0c1b245c75f8e43c59ca8ffeac292715e5078e631d0c9",
            "nonce": 118,
            "hash": "00a42f2cf32658666abac1e6dca4703f0195948914f74bfabba49831a8f07c82"
        },
        {
            "index": 2,
            "transactions": [
                {
                    "Customer": "atishay",
                    "Amount": "140",
                    "Drink": "Mocha Frappe",
                    "timestamp": "Sat Sep 25 21:40:29 2021"
                },
                {
                    "Customer": "mudit",
                    "Amount": "400",
                    "Drink": "Tea Latte",
                    "timestamp": "Sat Sep 25 21:40:55 2021"
                }
            ],
            "timestamp": "Sat Sep 25 21:41:00 2021",
            "previous_hash": "00a42f2cf32658666abac1e6dca4703f0195948914f74bfabba49831a8f07c82",
            "nonce": 136,
            "hash": "00f12d8cc4223fb71b1c330ce17be42bd4822422daf2325b081b0613010f23b2"
        }
    ],
    "peers": []
}

Our blockchain has the following functionalities:

• Get all the information of the Blockchain for the User.
• Immutability of the Blockchain (No one can change the already committed information)
• The timestamp of each Transaction is readily available using both the chain endpoint and time endpoint
• All the completed transactions are stored in the blockchain, we have both a verified (mined) pool as well as pending(uncomfirmed) transactions.
• We have also implemented a basic Proof of Work Algorithm where the hash of the block has to start with x numbers of 0's. We can set the difficulty (x) using the difficulty parameter in the BlockChain class. We took reference from the following code for the same implementation [Reference]
• The value of each nonce is calculated using the Proof of Work algorithm
• Each Block may contain multiple transactions, it can also contain a single transaction
• Each Block can have a maximum of 10 transactions after which it will automatically mine the block from the unconfirmed transactions pool.
• Cryptographic hash is been calculated using the hashlib with SHA256 algorithm in python
• The hash of the block and its previous block is available in the blockchain