Bitcoin : Block Structure

Block Structure (Size : 1MB)

Size	Field	Description
4 bytes	Block Size	Size of Block
80 bytes	Block Header	Block Header Info
1 ~ 9 bytes	Transaction Counter	Number of transactions in the current block (0 ~ 3000)
Variable	Transaction	Transaction list in Block

 

Block Header Structure

Size	Field	Description
4 bytes	Version	version info (95%^ => 2016 Block Upgrade)
32 bytes	Previous Block Hash	Previous Block Header Hash
32 bytes	Merkle Root	Hash Root of Transactions
4 bytes	Timestamp	Block generation time (UNIX Epoch)
4 bytes	Difficulty Target	Difficulty Level of PoW
4 bytes	Nonce	Result of PoW

 

Create Block

1. Select Mempool (level db) Tx (average : 2000)
2. Create Coinbase Tx (transaction for the revenue the block creator will receive)
3. Compute Merkle Root
4. Configure Block Header (version, previous block hash, Merkle Root, Timestamp, Difficulty (Difficulty changed based on 2016))
5. Find Nonce
6. Propagate Block 

 

How to connect to Block

 

 

Why Bitcoin imposed a limit on block size?

This is due to the performance of Database Lock to process transactions. 

This resulted in only about 2000 Tx per block. (3 to 7 tps)

Due to this block size limitation, miners have implemented ways to maximize transaction fees. 

They only select transactions with high fees or small transaction data volumes.

As the number of Bitcoin users increased, the price of fees increased.

In 2017, a hard fork (Segwit) occurred.