Quote from: J35st3r on June 05, 2013, 03:55:35 PM

Quote from: Frizi on June 05, 2013, 03:02:45 PM

The mined block header have a merkle root, which is a hash of all transactions in it. You can't simply change it, because the hash will change too. Until block is mined, it is easy to add transactions, because we can just change merkle root and continue hashing.

Hmm, I'm not convinced about this. The block hash is a search with a chance of 1 / (difficulty * 4294967296) success per operation. So if you throw away the block and start again you're just wasting effort. Or is this the fallacy of sunk cost?. Genuinely interested. My logic has been challenged once already since I escaped noobie land, so I'm open to education

Rolling a 1 on a die is search with a chance of 1 / 6 success per roll. If you roll the die and get something other than a 6, then pick the die up and roll again, are your chances any better or worse? Are you just wasting effort?

Every attempt to "solve" a block involves changing the data in the block header (by incrementing a nonce). Why is it any different to change the merkle root instead of the nonce?