Quote from: aminorex on June 08, 2014, 07:29:57 PM

Quote from: Peter R on June 08, 2014, 06:36:15 PM

Quote from: aminorex on June 08, 2014, 06:03:30 PM

If mining goes to PoS the cost tends to zero.

If the cost to secure the network tends to zero, then the cost to attack the network tends to zero is well.

The is the essence of the "nothing-at-stake" problem with PoS that, despite claims to the contrary, remains unsolved (and IMO very likely unsolvable).

Coins are a stake. Coins are not nothing when they have purchasing power. Is your concern that it is too easy to dominate purchasing power for a small currency? That makes sense when the market cap is low, but if you boostrap with PoW, to achieve market cap which is indefeasible in practice, then the problem is solved, is it not?

That's not the nothing-at-stake problem.

The attacker can attack the network using private keys that controlled coins in the past. He creates an attack chain starting from a point in the currently-dominant chain where those coins were valid to create a new attack chain. It is called "nothing at stake" because if the attack fails the already-spent coins he used to launch the attack simply remain worthless.