[yangl1996]

It does, however, allows "double spending" attacks. In such attacks the attacker first spends a coin to buy some real goods from the victim. She then launches a 51% attack on the blockchain and "rewrites" the ledger to remove the transaction to the victim. Now the attacker gets back her money, plus the goods from the victim.

[pat2man]

Yeah stores that accept crypto Currency need to understand this, or use an underlying abstraction that does. Of course for most chains this would make transactions very slow which is not good for commerce.

[urvader]

Stores that sell goods worth 700k in BTC?