This prophecy speaks of attacks against, and the collapse, of many, possibly all Crypto currencies, including BitCoin, Dogecoin, LiteCoin, and others.  Basically everything that's a crypto currency right now is going to go down, and go down hard at some point.  This doesn't mean that they won't recover and go big afterwards, or that others won't rise up on their place later on down the road.  What it's saying is that the current crop are going to either collapse, and rise again stronger than before afterwards, or they will take heavy damage that will result in their complete, or majority abandonment.

Again, this isn't going to hold true for ALL cryptos.  But it will for some.  The ways that this will happen includes the Fiat state of cryptos (ie, they have no backing like gold or silver, or even a government), as well as a major attack that brings the entire blockchain system to its knees, causing them to become unusable, worthless, or both.  If certain prophets are correct, this will be temporary, but it will be monumental too.  Some attacks are already underway even now as powerful forces are trying to collapse the Crypto industry.