This was raised in github issue:
https://github.com/marinecoin/marinecore/issues/4But I think this issue is too important so that it really should take one thread here for discussion with all parties. At recent past in 2018 summer, a miner attacked Marinecoin blockchain with tons of blocks (millions) at 1 second per blocks which destroyed MTC normal blockchain operation. ShorelineCrypto Exchange wallet was always couple of hours out of sync then and not usable. All deposit/withdraw was stopped.
This attack means that Marinecoin blockchain has security issue. One is instant mining prevention on above situation. Second is that this means potentially Marinecoin has 51% attrack risk on exchanges. Currently this is not big deal because only two exchanges have MTC trading, but this poses threat for more exchange listing in the future.
There might be many solutions to this. But I am proposing a Marinecoin Hard Fork to solve this issue with similar method of NewEnglandcoin (NENG). NENG published whitepaper v1.0 on this dynamic diff algo as anti-51% attack anti-instant mining method:
https://github.com/ShorelineCrypto/NewEnglandCoin/releases/download/whitepaper_v1.0/NENG_WhitePaper.pdfNENG v1.2.0/1.2.1 hard fork was released to implement this method. So far so good. Instant mining has been removed. Of course NENG is very different from MTC. I am proposing a difficulty spike of first 1 second as described NENG white paper can be implemented to block instant mining.
In the future, mining of Marinecoin can be further decentralized when the price of Marinecoin goes up in the future. Marinecoin is minable, 1 MTC per block. Not profitable today. But when Marinecoin price goes up in the future, CPU miners can join and mine Marinecoin. This is more of long term decentralization goal, no need for concern for short term.