Blockchain Interaction: Central Server & Miner Nodes

Step-by-Step Interaction When a User Adds a Transaction Request:

  User                             Central Server                          Miners (M1, M2, ...)
    |                                    |                                      |
    |------ Add Transaction -------------|                                      |
    |                                    |                                      |
    |                                    |                                      |
    |                               1. Broadcast Transaction -------------------| 
    |                                    |--------- Receive Transaction --------|
    |                                    |                                      |
    |                                    |                                      |
    |                              2. Add transaction to txn pool               |
    |                                    |                                      |
    |                                    |--------- Broadcast new txns -------->|
    |                                    |                                      |
    |                              3. Wait for block mining                    3. Start mining
    |                                    |                                      |---|
    |                                    |                                      |   |--> Do proof of work
    |                                    |                                      |---|
    |                                    |                                      |
    |                                    |                                      |---|
    |                                    |                                      |   |--> Successfully mine a block
    |                                    |                                      |---|
    |                                    |                                      |
    |                                    | <----- Broadcast new block --------- |
    |                              4. Verify Block                             4. Verify Block
    |                              5. Add Block to chain                       5. Add Block to chain
    |                              6. Adjust difficulty                        6. Adjust difficulty
    |                                    |                                      |
    |                                    |                                      |
    |                                    | ----- Broadcast new block ---------> |
    |                                    |            to                        |
    |                                    |        other miners                  |
    |                                    |                                      |
    |                                    |                                      |
    |------- Notify users of success ----|                                      |

Central Server Responsibilities:

1. Broadcast Transaction: When a user adds a new transaction, the central server broadcasts it to all connected miners.

2. Manage Transaction Pool: The server adds the transaction to its own transaction pool and removes transactions that are already included in a mined block.

3. Broadcast New Transactions: The server keeps miners updated by broadcasting new transactions regularly.

4. Verify and Add Block: Once a block is mined by any miner, the central server verifies it and broadcasts the new block to the rest of the miners.

5. Adjust Difficulty: After receiving each new block, the server adjusts the difficulty level to maintain a steady block time.

Miner Server Responsibilities:

1. Receive Transactions: Each miner receives new transactions from the central server and maintains its own transaction pool.

2. Mine Blocks: Miners mine blocks at a fixed interval by performing Proof of Work (PoW). This involves finding a valid hash based on the difficulty level.

3. Broadcast Mined Block: After successfully mining a block, the miner broadcasts it to the central server, which further distributes it to all other miners.

4. Verify Block: Each miner verifies the received block and checks if the chain is valid. Smaller or erroneous chains are rejected.

5. Update Blockchain: The miner updates its local copy of the blockchain and adjusts the mining difficulty based on the central server’s broadcast.