4 ms·
Using your definition, all cryptography is also probabilistic. It's technically correct, ie. there's a risk that someone guesses your AES key, but it's practica
by runeks 9y ago
Using your definition, all cryptography is also probabilistic. It's technically correct, ie. there's a risk that someone guesses your AES key, but it's practically irrelevant because the probabilities involved are so small (and key sizes can be adjusted to make guessing as improbable to succeed as we want).
- andrewla 9y agoThis is not the aspect that is considered to be probablistic. The problem is that forks can happen by design -- blocks can be orphaned and the tree can be reorganized. So a transaction is only final so long as it is on the main chain; if the main chain switches to a forked chain that does not contain your transaction, then it is not settled; the resulting coins cannot be spent. There are attack scenarios, but even without those it is possible for forks to occur; single-block forks are common (so-called "orphaned blocks") due to some combination of network latencies and chance. Longer forks may be possible if there are more dramatic breaks in network connectivity. The original whitepaper originally advocated waiting for six blocks before a transaction is considered "settled". That's probably high, but the guarantees are strictly probablistic; any software dealing with bitcoins has to be aware of the possibility of reorganizations.