Newbie Calder started an interesting discussion about a Stanford paper on Bitcoin that discussed decentralized checkpointing. The basic idea is for nodes to be skeptical of blocks that change transactions that they themselves witnessed in the past.
https://bitcointalk.org/index.php?topic=186097.0anti-scam is right, you'd have to be careful with the math so you didn't wind up with blockchains accidentally diverging all over the place. Let's give ourselves a few definitions so we're on the same page.
The credibility C of a blockchain is a function of the blocks in that chain. The work W is a measure of how much work went into a given block. The age A of a block is how long ago this node first saw that block. Right now, this looks like:
C = sum of W(b)
But there's no reason it couldn't look like this:
C = sum of W(b) * F(A(b))
where F(t) is some function of the a block's age.
The hard part is how you pick for F(t). Discuss!
What do you think? Is a scheme like this feasible?
