Orphan Block

1. mining

An orphan block is a valid block in a blockchain that is not included in the current longest chain. These blocks are fully valid and verified, they simply are not on the main chain.


"When two miners solve a block at nearly the same time, it might be that some nodes in the network receive one block first and others receive the other block first. Both blocks are added to the blockchain, but eventually one block becomes an orphan."

2. causes

Orphan blocks occur when two miners produce blocks at similar times or when an attacker attempts to reverse a transaction. The network will only adopt one branch, and the block that is not selected becomes an orphan block.


"If two miners solve a block at the same time, the network might be split on which one to add to the blockchain. The tie is broken when the next block is solved, effectively orphaning the other block."

3. consequences

Miners of an orphan block lose the block reward and the transaction fees they would have earned. It's as if their work never happened, even though the block they solved is just as valid as any other block.


"Mining an orphan block is unfortunate for the miner because even though they did the work to solve it, they receive no Bitcoin reward or transaction fees."

4. prevention

The probability of creating an orphan block is reduced by having a good connection to the Bitcoin network, as this ensures that you hear about blocks first.


"Miners can reduce the chance of creating an orphan block by ensuring they have a reliable and fast connection to other nodes in the Bitcoin network."

* All terms and definitions may update as the Cryptionary improves.