Something very interesting Andreas M. Antonopoulos says on "Bitcoin competitors."
Please read this, it's long but very interesting.
"The vast majority of Altcoins operate using what we call the Nakamoto consensus." The "consensus Nakamoto" says the chain of proof of work longer determined by the algorithm SHA256.
Some algorithm used SHA3 or Scrypt algorithm or different forms of hashing algorithms, but still implement the consensus Nakamoto in terms of getting the chain of proof of work longer.
But there altcoins using other forms of consensus, consensus modified chains that take into consideration orphaned, for example, Ghost (what I described before, we have some experimental implementations that)
And there are mechanisms consensus instead of using proof of work are based on proof of stake, or Delegated proof of stake.
We are seeing all kinds of new algorithms consensus emerge, how many of these can escalate to a level of safety that is resistant to global attacks? So far, one ... Bitcoin.
But ... That does not mean one can not climb.
What is difficult, however, is that if you try to scale a consensus algorithm today, you have to climb before being attacked scale.
You have to build an industrial infrastructure hashing, or mining, or user base, or an economic base that is large enough to resist the attack before being attacked ....
Bitcoin did this because everyone ignored him for a couple of years because they did not think it was important. And by the time everyone realized and thought "Okay, maybe this is important and worth attack" and was strong enough and could not be attacked.
And then the strength of the network has exceeded the adoption and demand for the attacks to be extremely resistant to attack.
The problem is: you can not do that again ...
Because if you really got an algorithm very innovative consensus, and people think it will be valuable, and think it will be valuable enough to join the consensus algorithm and undermine for it, they will also think that is enough valuable to be attacked, and there is no place to fly under the radar ... "