Why is Bitcoin Cash much more vulnerable than Bitcoin

Yesterday I posted (Bitcoin cash v litecoin) , under the post was a little arguments with me and read.cash author about BTC and BCH.And under those reasons I realized the is more exploit of BCH just like Btc.

Examples is the double spend which was found in Btc years ago.

In BCH there are multiple ways to execute a double spend attack and all of them are easy (ABC)

So far only 5 have been divorced

• Race Attack

This attack can only be executed when 0-conf transactions are accepted. In BTC 0-conf is not done and in BCH it is used and heavily promoted, so only BCH is vulnarable. When BCH finally get adopted by real users and blocks become filled up (or spam, can eventually be done by the attacker), this attack becomes even easier because slower block propagation will make it take longer to detect.

• Finney

Also here only BCH is vulnerable because the use of 0-conf transactions. Furthermore, because BTC miners can shift temporary to BCH from BTC there are much more possible attackers (add up the hate against BCH). Also, when BCH blocks become full and thus propagation time is longer the attack becomes easier because the other miners are delayed more and this will give the attacker more time to execute his attack before other miners interrupts him by finding another block.

• Vector76 attack

This attack is possible on BCH and BTC as well. However, on BCH it is way easier to execute because it cost way less to mine a block and the mining cost of one block have to be sacrificed for the attack. Furthermore, there is a way bigger pool of possible attackers because BTC miners can shift temporally to BCH to execute the attack.

• Alternative history attack

This attack requires a lot of hash power and in case of a failure the ‘work’ that is used will be lost with financial damage as result.

When the attacker owns 0.4% of the hash power his chance to be successful is just over 50%. Between 0.4 and 0.5% of the hash power his chance will increase from 50 to 100%. It is very hard to take control over 40 to 50% of the BTC hash rate, but only 10% of the BTC miners will own 50% of the BCH hash power when they move over temporary for the attack. This makes BCH extremely vulnerable even with transactions with more than 6 confirmations!

• Majority attack

This attack is really hard and expensive to execute on BTC and when individual miners see that a pool almost reach 50% they will leave this pool to avoid the possibility of an attack to maintain their future income. On BCH only 10% of the BTC miners have to move to BCH to execute the attack, when a part of the attackers is already on the BCH chain a way smaller part of the BTC network is needed. The existence of BCH is increasing the risk for BTC, because it is undermining the game theory as described on the Wiki, miners can move to BCH after attacking BTC so their hardware is not totally obsolete.

attacker needs 10% of the BTC hash rate to shift over to BCH instantly to own 50% of the hash rate. When the miners shift slowly they will make other miners leave because the difficulty goes up and thus the profitability goes down. In that case they need way less than 10%, some more than 5%. The downside is that a big attack will lower the value of the already minted BCH and it cannot be sold immediately. This have to be figured out by the attackers what is more profitable in the end.