Thanks, so they can't get rid of that "trusted/centralization" part right?
It is just a once off thing.
A better way to think of it is that the POW stage is an initial "fair" giveaway stage. Once it is done, the checkpoint is part of the protocol.
The chain is
defined as having a particular hash as genesis and that block 50000 hashes to . The only difference is that it takes a while to find the 50000th block.
If you joined after the 50000th block, there is no difference between the hard-coding the genesis block into the client (which Bitcoin does too) and hard-coding the 50000th block.
It is fully p2p after the 50000th block.
Ah, I see, so no mining will happen after the 50000th block right? The only way to get any coin afterwards would be to obtain from those who already have it?
Also your ISP maybe playing con tricks on you and you never get the right checkpoints
There is only 1 checkpoint and it has to be signed by the original developer (or group of trusted individuals). They promise to only sign one checkpoint.
The ISP can't fake that signature. The checkpoint signature would be part of the protocol.
They can't really stop you from getting the signature. It only happens once, and they would have to scan everything that goes to you to block it. This would require blocking you from making any encrypted connection at all. That isn't feasible.
While hardcoding in the Bitcoin client remains the status quo, I would have no problem telling a fake chain from the real one without such hardcoding, as I could always check if the difficulty of the newest blocks meet the right target, assuming no one is attacking me with a hundred million-dollar farm of course, it is on the other hand much easier to just change the content of a software as the cost for hijacking a communication channel is much lower, also the developer may have difficulty proving himself to be the...developer without an external authority, similar things happened in the countless cases of internet scams.