The term merged mining refers to the simultaneous minting of two or more cryptocurrencies without sacrificing overall mining performance. By using Auxiliary Proof of Work (AuxPoW), a miner can leverage their computational power to mine blocks on multiple chains.
Understanding the term
The concept of Auxiliary Proof of Work (AuxPoW) is that the work done on one blockchain can be leveraged as valid work on another blockchain. Here, the blockchain providing the proof of work is called the parent blockchain, while the blockchain that accepts it as valid is called the auxiliary blockchain. To perform merged mining, the cryptocurrencies must have the same algorithm. For instance, Bitcoin uses SHA-256. This means any cryptocurrency that uses SHA-256 can be mined along with Bitcoin.
In merged mining, the parent blockchain does not have to go through any technical modification. However, the auxiliary blockchain needs to be programmed correctly to receive and accept the work of the parent chain. Normally, a hard fork is required for adding or removing support for merged mining.
As long as enough miners agree to adopt merged mining, it can reduce the possibility of 51% attacks. 51% attacks occur as a result of a single miner or mining group taking majority control of a PoW blockchain and double spending coins. By tapping into the hashing power of a larger parent chain, merged mining can protect both cryptocurrencies from the attack.