Dmitry Khovratovich and Alex Biryukov created and developed the EQUIHASH algorithm. Biryukov is a professor from the University of Luxemburg, working in computer science. Khovratovich works independently as a post-doctorate researcher with a focus on block ciphers and hash functions.
There is a specific concept behind Equihash: it’s called the birthday problem. A simple description would it explain it like this: when faced with a random selection of individuals, what is the probability that a pair of individuals would have the same birthday? In theory, when you have 367 people you will get a 100% probability that there will be two birthdays that are the same.
The interesting part is that when you have just 70 people, you have a near hundred percent probability – in fact, a 99% probability. It is this unique fact that Equihash uses when trying to process transactions in its blockchain – it uses an algorithm which aims not for 100% certainty, but for sufficient certainty to make sure a transaction is verified using the minimum amount of resources.
Cryptocurrencies that make use of Equihash can ensure that they are more decentralised. Because Equihash requires a lot of memory when it processes transactions it means that mining the coin will not be concentrated on a few elite individuals that have special mining equipment. Therefore, Equihash contributes to making digital currencies more democratic – it benefits any cryptocurrencies that make use of Equihash as its mining algorithm.
Equihash was originally developed as a hashing algorithm to be used with Zcash, a coin that was developed in order to give the users of Zcash more privacy when using its network – compared to other alternative cryptocurrencies. Equihash eventually was improved and modified and used as part of the Zerocash system – and as the basis for Zcash since 2016.
Zcash publishes all transaction to a blockchain, just as with many other coins, but Zcash users have an additional feature – the ability to use an optional setting for privacy. When used the sender can hide who sent and who received the coins, alongside the amount of coins that they sent. It is a big advancement in the cryptocurrency world where the decentralised nature of blockchains usually mean that all transactions can be seen by everyone.
Proof-of-work is the method behind Equihash and the algorithm is memory orientated. The result is that mining power is related to how much memory a mining system has. As an indication, you need one gigabyte of RAM for every mining thread you want to run.
Equihash’s creators think that is not likely that anyone will think of an ASIC miner which can mine Equihash anytime soon – at least not an ASIC rig that can be built cost effectively. This is because Equihash’s algorithm uses a memory intensive algorithm to solve for blocks. It’s an algorithm that works well on any general-use computer that has a lot of RAM – it does not depend on special processors so cannot be accelerated by an ASIC rig with lots of special processors. Besides, ASIC mining rigs do not have sufficient memory on board to solve for the Equihash algorithm.
Instead, Equihash-based coins can be mined using your usual home computer with its standard CPU and graphics chip, as long as you have enough RAM on your computer.
So, the advantages of Equihash is that for the moment there are no ASIC miners that can hash the algorithm which means that home computers are great for mining. However, you need some specific knowledge to set up an Equihash mining rig – you can’t just buy it off the shelf like an ASIC mining rig. At the moment, only Zcash can be mined using Equihash.