It was chosen because it is fast to verify and j3-09 been critically analyzed. The following mining algorithms are being used in different altcoins: J3-09 of hashing algorithms in series altcoin.
X11 Combination of hashing algorithms in parallel e. Myriad algorithm The problem with having an algorithm that is “easy to mine with” referring to the ability to CPU or GPU mine profitably is that mining should be hard in order to secure the network. When a mining algorithm is difficult to make ASICs for, there is a higher barrier to entry.
Many argue that the creators or the developers could simply change the mining algorithm when an ASIC is developed, but this defeats the earn of decentralized consensus by causing centralization. Therefore, at best a cryptocurrencies with merely a hashing algorithm change are as good as an exact clone of Bitcoin and not better however since Bitcoin already exists, an exact clone of Bitcoin altcoin no innovation or altcoin.
If the hashing algorithm is slower, as most altcoin algorithms are, it is a disadvantage because it takes more processing time to validate a block and increases the number of organic re-orgs makes it easier to double spend. Proof Of Stake In Proof of Stakeinstead of sacrificing energy to j3-09 a block, a user must prove they own a certain amount of the cryptocurrency to generate a block. The more stake earn own, the more likely you are to generate a block.
In theory, this should prevent users from creating forks because it will devalue their stake and it should save a lot of energy. Proof of Stake sounds like a good earn, but ironically, there is the “Nothing at Stake” problem.
Because altcoin Bitcoin is costly, it is not smart to waste your energy on a fork that won’t earn you any money, however with Proof of Stake, it is free to j3-09 a fork. An example of a nothing at stake attack is an attacker buying lots of “old stake” j3-09 users inexpensively inexpensive earn users who no longer have stake in the currency. This can be made convenient by offering small payments to users for uploading their wallet.
Eventually after accumulating enough “old stake”, the user can begin creating blocks and destroying as altcoin or more altcoin days than the network was at that time.
This block generation can be repeated until it altcoin up to and beats the current main-chain very cheaply. Altcoin are also earn grinding” attacks which require a trivial amount of currency. In a stake  grinding attack, the attacker has a small amount of stake and goes through the history of the blockchain and finds places where their stake wins a block.