Transactions are bundled together in a ‘block’.
- The miners verify that the transactions within each block are legitimate by solving the hashing algorithm puzzle, known as the “proof of work problem”.
- The first miner to solve the block’s “proof of work problem” is rewarded with a small amount of cryptocurrency.
- Once verified, the transactions are stored in the public blockchain across the entire network.
- As the number of transactions and miners increase, the difficulty of solving the hashing problems also increases.
Although PoW helped get blockchain and decentralized, blockchain betting trustless digital currencies off the ground, it has some real shortcomings, especially with the amount of electricity these miners are consuming trying to solve the “proof of work problems” as fast as possible. According to Digiconomist’s Bitcoin Energy Consumption Index, Bitcoin miners are using more energy than 159 countries, including Ireland. As the price of each Bitcoin rises, more and more miners try to solve the problems, consuming even more energy.
All of that power consumption just to validate the transactions has motivated many in the digital currency space to seek out alternative method of validating the blocks, and the leading candidate is a method called “Proof of Stake” (PoS).
PoS is still an algorithm, and the purpose is the same as in the proof of work, but the process to reach the goal is quite different. With PoS, there are no miners, but instead we have “validators.” PoS relies on trust and the knowledge that all the people who are validating transactions have skin in the game.
This way, instead of utilizing energy to answer PoW puzzles, a PoS validator is limited to validating a percentage of transactions that is reflective of his or her ownership stake. For instance, a validator who owns 3% of the Ether available can theoretically validate only 3% of the blocks.
In PoW, the chances of you solving the proof of work problem depends on how much computing power you have. With PoS, it depends on how much cryptocurrency you have at “stake”. The higher the stake you have, the higher the chances that you solve the block. Instead of winning crypto coins, the winning validator receives transaction fees.
Validators enter their stake by ‘locking up’ a portion of their fund tokens. Should they try to do something malicious against the network, like creating an ‘invalid block’, their stake or security deposit will be forfeited. If they do their job and do not violate the network, but do not win the right to validate the block, they will get their stake or deposit back.
If you understand the basic difference between PoW and PoS, that is all you need to know. Only those who plan to be miners or validators need to understand all the ins and outs of these two validation methods. Most of the general public who wish to possess cryptocurrencies will simply buy them through an exchange, and not participate in the actual mining or validating of block transactions.
Most in the crypto sector believe that in order for digital currencies to survive long-term, digital tokens must switch over to a PoS model. At the time of writing this post, Ethereum is the second largest digital currency behind Bitcoin and their development team has been working on their PoS algorithm called “Casper” over the last few years. It is expected that we will see Casper implemented in 2018, putting Ethereum ahead of all the other large cryptocurrencies.