Bitcoin Block Mining Simulator

A high-fidelity simulator that authentically replicates the core mechanics of the Bitcoin protocol, including the mempool, transaction selection, and the genuine double SHA-256 proof-of-work algorithm.

Overview

This application acts as a true-to-life representation of Bitcoin mining. It requires the player to select the most profitable transactions, bundle them into raw strings, and engage an automated SHA-256 hashing loop to brute-force a valid block hash that meets the network's difficulty criteria.

Rules (Based on the Bitcoin Protocol)

1. Transaction Validity: A transaction is only valid if the sender has sufficient balance to cover the transaction amount and miner fee.
2. Mempool: Unconfirmed transactions broadcasted to the network are held in the mempool.
3. Transaction Selection (Fee Market): Miners are economically incentivized to maximize profit. You must select exactly 3 transactions with the highest miner fees.
4. The Target Hash (Difficulty): The network algorithmically generates a 64-character hexadecimal target string. To be valid, a block's final hash must be numerically lower than this target hash (which generally means it must start with a specific number of leading zeros).
5. Double SHA-256 Hashing: Bitcoin uses a two-step hashing process. First, the raw transaction data is hashed. Second, a "nonce" is appended to this first hash, and the combined string is hashed again to produce the final block hash. Final Hash = SHA256( SHA256(Raw_Transactions) + Nonce )
6. Proof of Work (Mining): A miner must rapidly increment the "Nonce" (Number used once) and recalculate the final hash until the output is smaller than the Target Hash.

Steps to Play (Easy Version)

1. Review the Mempool: Observe the unconfirmed transactions available in the mempool. Some transactions might be invalid or attempt to spend more than the available balance.

2. Select Transactions: Choose exactly 3 valid transactions. You must strictly follow the fee priority rule, picking the ones with the highest fees.

3. Check Balances: Ensure that the senders have enough balance to cover the total amount and fees for all your selected transactions. The system will reject invalid selections.

4. Calculate Block Value: The application computes a block value based on the selected transactions' amounts, fees, and the mathematical values of the sender and receiver names:

   Block Value = Sender Names Number + Receiver Names Number + Amount of BTCs + Fees
   

5. Find the Nonce: Guess a positive number for the Nonce. Your goal is to satisfy the equation:

   Previous Target + Nonce + Block Value = Current Target
   

   Tip : Genesis Block has 0 Target Value , based on the fact that there was no transactions!

6. Mine the Block: Submit your Nonce. If the equation holds true, the block is successfully mined, balances are updated, and the network advances to the next block with a new target. If incorrect, try another Nonce.

Steps to Play (Hard Version)

1. Review the Mempool: Observe the unconfirmed transactions. The mempool may contain fraudulent transactions attempting to spend unbacked funds.
2. Select Transactions: Pick exactly 3 valid transactions by strictly following the fee priority rule. The system will reject invalid selections.
3. View the Cryptographic State: Once selected, the system will generate your raw transaction string and the initial Transaction Hash. It will also generate the network's Target Hash for the current block.
4. Start Mining: Click "Start to increase nonce". Your computer will begin rapidly hashing the data, incrementing the nonce automatically on each attempt.
5. Live Verification: You can use the "Live SHA-256 Verifier" panel at the bottom to manually input the raw transaction string and nonce to verify that the cryptographic math is authentic and accurate.
6. Mine the Block: Once the algorithm randomly discovers a nonce that produces a valid hash with the required leading zeros, the mining will complete. Click "MINE BLOCK!" to broadcast the block, update the global balance sheet, and advance the blockchain!