Ethereum: Understanding Bits and Difficulty in a Block Header
The block header of an Ethereum blockchain is a critical component that contains various information about the current state of the network. A key aspect of this header is the difficulty, which is measured by its value.
In this article, we’ll go into detail about how the number of transactions per block (TPB) and bits per block (Bpb) are calculated, as well as what block difficulty means.
Block Header Overview
An Ethereum block header typically consists of 16 fields:
- “Timestamp”: the time the block was created.
- “Hash”: a unique fingerprint of the block header used for verification and validation.
- “Difficulty”: measured by its value (more on this below).
- “Target Difficulty”: the target difficulty for blocks to be added in the future.
- “minDifficultyValue”: The minimum difficulty value required for a new block.
- “maxDifficultyValue”: The maximum difficulty value allowed for a new block.
- “number of confirmations”: The number of confirmations (or “votes”) the block must receive from nodes in the network to be considered valid.
- “size”: The size of the block header in bytes.
- “difficultyTargetHash”: A hash of the target difficulty value used for verification and validation.
- “previousHash”: The hash of the previous block header.
- “index”: The index of the current block within the chain (0-indexed).
- “cycleStartBlockHash”: The hash of the start block of a cycle.
Difficulty
Difficulty is measured in value and represented as a decimal number. In Ethereum, difficulty is calculated using a complex algorithm that takes into account several factors, such as:
- Network congestion: the amount of traffic on the network.
- Block size: the size of each block header.
- Difficulty target: the minimum difficulty required for a new block to be added.
The current difficulty is 3,007,383,866,429.73. This means that approximately 3.01 billion hashes (i.e. blocks) with the same difficulty value would be required to reach this point in the network’s history.
Bits per block
To calculate bits per block, we need to divide the number of bits by the number of bytes in a block header. According to the Ethereum specification, each byte contains 4 bits.
The total number of bytes in an Ethereum block header is 32, which is approximately 1,265,728 bits (32 x 40 = 1,295,120).
To calculate bits per block:
Bits per block = total bytes / number of bytes/block
= 1,265,728 / 32
≈ 39,870 bits
In summary, the current difficulty on Ethereum is around 3.01 billion hashes with a value of 73.73 decimal places and the number of bits per block is around 39,870.
The next challenge for the network is to reach the target difficulty of around 1,500,000,000 hashes (150 billion) with a difficulty of around 30 decimal places.
