Hi folks, I often read that many people are afraid of so called 51% attacks. I really don't understand the big deal about it.
********1st problem: Double Spend Attack*********
Here my solution: Can't we agree that our full Bitcoin Nodes never automatically overwrite these parts of the Blockchain that are older than let's say 1 hour (or 6 confirmations). Normally orphaned blockchains never contain more than one additional block, so there should not occur any problems.
Actually, this IS already implemented, as I described in the following article:
http://btc-base.blogspot.sk/2014/01/bitcoin-transactions-why-it-is.htmlTheoretically, though, I am not sure if the attacker couldn't try to fake the timestamp (he would set the timestamp of the first "private" block around one hour to the future).