Hacker News Reader

Comment by man-and-laptop | Hacker News Reader

It would be nice if this were used as the PoW problem for a blockchain. Since the Mersenne Primes are rare, the PoW problem shouldn't be to find new Mersenne Primes directly, but something that could make indirect progress on that. Also the blockchain should solve an actual problem, such as torrent tracking or DNS.

It makes me think that there should be a list of viable uses of blockchain, and another list of interesting problems that could be moulded into PoWs, and they should be paired up into blockchains.

View on HN

One problem is that a black hat could solve a lot of primes in secret, and then use those for a double spend attack.

Specifically,

a) Spend some coins to buy some other cryptocurrency

b) use all their secret primes creating a bunch of new blocks on a branch where they haven't spent their money. Since this is the longest branch now, all the other clients accept they haven't really spent it.

c) buy the other cryptocurrency again on this new branch.

No. The PoW problem should be derived according to the current state of the blockchain. That makes "solving a lot of primes" in secret inapplicable. You read my post far too literally.

The idea is to combine the ideas behind Namecoin with Primecoin.

Actually, the problem is that there is no way to control the difficulty. Finding new primes would be harder and harder, but you want the difficulty to adjust up or down to target a block time. Not sure how primecoin approached that problem?

Update: found some clues here, https://www.reddit.com/r/primecoin/comments/1i71ma/strange_b...

https://gridcoin.us/

How would you measure amount of work you want to reward with a coin? In both DNS and torrent examples one can influence a supply of work to be done rather easily

It's a broad idea to construct a secure PoW, with all that's required to make it secure, but to try and make it applicable to areas like number theory. See PrimeCoin for a successful example.

Also your concerns are unfounded: See Namecoin and Primecoin. I'm thinking these two ideas could be combined.

Reply on news.ycombinator.com