Quote from: yangchigi on September 28, 2018, 03:43:34 AM

it's same way too 51% attack and withholding attack.

if attacker can withholding block ,how attach network without 51% hashrate ?
if attacker can 51% hashrate , how attack without withholding block ?

two word looks like different , but two word same way attack network.

It's true that both of them are ways to attack network, however there are few major difference

51% attack

Require at least 51% of total hashrate

Can be used invalidate recent transaction/block

Mainly used to trick merchant

holding block/selfish mining

No minimum %, but the higher is more effective

Can't be used invalidate recent transaction/block

Mainly used to make other miners waste their time/resource

P.S. The table on post and preview totally different, gonna fix it later.

More info :
https://bitcointalk.org/index.php?topic=4998410.msg45110560#msg45110560
https://en.bitcoin.it/wiki/Majority_attack

Quote from: yangchigi on September 28, 2018, 03:52:25 AM

how make checkpoint every n block in blockchain software?
if make checkpoint every n block in reference site , how trust reference site.
trust foundation work only insert trust block, it's not reason to turn back to centralized system.

It's just random thought after saw how bad this PoO proposal. But basically, each nodes make their own checkpoint every n blocks and outdated nodes will ask checkpoint from other nodes (as opposed from asking block header first) before send blocks/block headers.

It's not practical/really useful anyway since it's only useful for nodes that online 24/7 and most client already set their own checkpoint.