It was chosen because it is fast to verify and has been critically analyzed. The following mining algorithms are being used in different altcoins: Combination of hashing algorithms in series wiki.
X11 Combination of hashing algorithms in parallel e. Myriad algorithm The problem with having an earn 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 purpose 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 Wiki has no innovation or value.
If the hashing algorithm wiki 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 Earn In Proof of Stakeinstead of sacrificing energy to mine a block, a user must prove they own a certain amount of the cryptocurrency to generate a block.
The more stake you own, the more likely altcoin 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 idea, but ironically, there is the “Nothing at Stake” problem. Because mining 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 mine a fork.
An example of a nothing at stake attack is an attacker buying lots of “old stake” from users inexpensively inexpensive to 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 coin days than altcoin network was at that time.
Статусная дороговизна или доступная дешевизна?
This block generation can be repeated until it catches up to and beats the current main-chain very cheaply. There are also “stake 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. In order to consecutively earn, they modify the next block header until some stake they own wins once again. This attack requires a bit of computation, but definately isn’t impractical.
Because these attacks exists, including Peercoin  and Blackcoin  proof of stake cryptocurrencies have “master” public keys that control the blockchain.