>>1194>parties that hold 51% or sometimes less can forge transactionsI'm fairly sure they already solved that problem directly on the algorithms used. However, I don't know if said algorithm are widespread enough; they should be at least on the major currencies, but I don't really follow that closely the various implementations.
>>1184>Then where does the crypto come from?The thing is, the point of a blockchain (or whatever IOTA uses) is not the currency, but rather the fact that once a block is inserted, then whatever is written inside the block can't be changed.
Let me explain it with an example: say you and a friend of yours exchange some goods, e.g. you give 10 apples and receive 10 oranges from your friends.
Because you want to record this exchange so that no one can claim the exchange didn't happen or that happened differently, you place it on the blockchain and have a third person, a witness, sign it.
Now that the block is inserted in the chain and signed, no one can claim that the exchange of 10 apples for 10 pears never happened.
Now, the witness didn't receive anything directly from the exchange yet had to participate, so to compensate him for the service, a certain amount of currency is given to him. It could be an actual fiat currency (e.g. 10 american dollars), but if the witness is not physically present (like it is with the internet) then a different currency has to be used; this currency is generated by the blockchain and it's the cryptocurrency.
IOTA does not need a currency because it's not compensating a witness of an exchange; rather, it asks everyone connected to the "tangle" to witness and sign the exchange.
Basically, it's not about the money but about confirming that a certain exchange happened with certain terms and conditions and that no one can say otherwise.