When one transaction is broadcasted, what is the probability that it won't be confirmed? (By probability, I mean the observed probability on the blockchain. If a person intentionally spend twice 1 bitcoin, I imagine that the probability is roughly 0.5). What are the reasons that the transaction will be invalid.
- one of the reason is double spending.
Now since every 10 minutes, a block is mined. After 10 minutes, what is the probability that the transaction will be invalid. I read that 6 confirmations (so 6 blocks) is a good number.
Now after 60 minutes, what is the probability of invalidating the transaction?