Casper is the POS protocol that Ethereum has chosen to go with.

So how is Casper different from other Proof-of-work and Proof-of-stake protocols?

Ethereum protocol Casper


PoW Issues

Main page: Proof-of-work

Most cryptocurrencies (including Bitcoin and Ethereum) use the “Proof-of-Work”.

PoW as a process has the following steps:

• Miner solves a cryptographic challenge to “mined” a block for the blockchain. This energy-consuming process • When the problem is solved, the miner sends the block to the network to check

  • The block is checked for belonging to the blockchain

Problems with proof of work

  • Mining (solution of algorithm) – energy-consuming process
  • Big mining pools have more chances of profitable mining than single mining.

• Only five large mining pools share 65% of the mining of Bitcon market • These 5 mining pools can teaming up to launch 51% attack

PoS Issues

Main page: Proof-of-stake

This is how the process will work:

  • Validators will need to freeze some of their coins as a stake.

• After checking the blocks, the validators will confirm it by putting their stake on it. • If a block is added, the validators will receive a reward proportional to their rates.


If you use POF When you as a miner wants to make a fork. You have use the whole hash, it won’t be enough, and it’s hard to attract other miners. They else will still continue to mining on the original network because it is more profitable and has fewer risks. PoW is expensive, so it makes no sense to spend a lot of resources on a block that will be rejected by the network. Therefore, less likely to forks.

If you use POS:

As a validator, you can send your money to the blockchain without fear of consequences. No matter what happens, you will always win and have nothing to lose, despite how malicious your actions maybe.

This is called the “Nothing at Stake” problem, and this is something that Ethereum had to address. They needed a protocol which could implement POS and mitigate the “” problem. The developers of Ethereum had originally planned to go to the PoS and to alleviate the problem of new forks.

Casper differences from other PoS

Casper is a POS Protocol that uses Ethereum.

Chief developer Vlad Zamfirescu

how protocol Casper wokes

This is how Ethereum protocol Casper wokes:

  • Validators put part of their Esters as a share.
  • After that, they will start checking the blocks. When they discover a block that they believe can be added to the chain, they will confirm it by putting on it.
  • If a block is added, the validators will be rewarded in proportion to their rates.
  • However, if the validator acts in a malicious way and tries to make “Nothing at Stake”, it falls into the ban, the whole share will be canceled.

Casper is different from most other PoS protocols. Attackers have something to lose, so it is impossible that nothing was put at stake.

Casper is an Association of two Ethereum research projects:

  • Casper the Friendly Finality Gadget (FFG)
  • Casper the Friendly GHOST: Correct-by-Construction (CBC)

Casper FFG aka Vitalik’s Casper is a hybrid POW/POS consensus mechanism. This is the version of Casper that is going to be implemented first. This is pretty much designed to ease the transition into proof of stake. The way it is designed is that there is a proof-of-stake protocol overlaying on top of the normal ethash proof of work protocol. So while blocks are still going to be mined via POW, every 50th block is going to be a POS checkpoint where finality is assessed by a network of validators.

See Also on BitcoinWiki



White Paper