We really have seen many successful, large scale attacks on digital infrastructure. The 1980s superhacker never took control of traffic lights and caused nationwide havoc.

All the security people I know think that it is possible though, and likely to happen sometime. I feel like the longer it takes, the worse. We need something to shake us out of complacency.

  Cashless transactions require a third party

Cryptocurrency.. (miners are decentralized and don't require you to trust them)

The network is still the third party.

With cash, or bottle caps, or any physical token, all you need are two people that agree it has value. Possession is the ledger.

The network can still run between those two people alone (if consolidation is solved).

Nature has an elegant solution to the double-spending problem for physical commodities.

If only there was a way to timestamp digital transactions without a write-only ledger...

Yes... I wonder how Nature implemented that...

By dropping transmutative alchemy from the sprint, allowing the implementation of a capability system on top of a now unforgeable subset of existing resources...

Sounds like the whitepaper for this week's hottest ICO!

Thank you so much. I'm on the verge of framing this and putting it on the wall. Cubicle wall, but still.

  all you need are two people that agree it has value

Wrong. All currencies need a network (physical or otherwise) or else it's just bartering between two objects.

The entire idea of currency requires a network of people who project a common value in the implemented token/object/hash.

Transactions still have to be approved by the network. ATM it's pretty slow. And many coins have one pool with majority of the hash rate --> not so decentralized

That's because rejecting RBF transactions without making it part of consensus is not incentive compatible

you still need permission to do it, even if you don't need to trust the permission granter.