Quote from: cr1pton00b on January 01, 2018, 05:34:49 PM

Quote from: sboz on January 01, 2018, 05:22:35 PM

Quote from: cr1pton00b on January 01, 2018, 12:54:41 PM

Quote from: sboz on January 01, 2018, 04:29:21 AM

Quote from: cr1pton00b on January 01, 2018, 12:37:54 AM

5. The Man in the Middle attack.

If an attacker succeeds to put himself between a merchant and the RaiBlocks network he can just filter the double spending payment packets, and the merchant will never know that he is receiving a double spending. The Raiblocks network will discard that payment while the merchant will accept it.

https://s18.postimg.org/7pnm6yweh/doublespend.png

Couldn't the same MitM attack be used in a bitcoin transaction? Connect to all the peers of a merchant and mine 6 blocks containing the double spend while filtering out all longer blocks so the merchant accepts the transaction as valid.

No, because if you MITM a bitcoin merchant, you still have to mine 6 blocks with the difficulty bit set by the real network. And the difficulty only decrease by 1/4 every 2015 blocks. It will be impossible for an attacker to have such power.

Of course an attacker can mine 6 blocks. It will take more than an hour but it doesnt matter because all longer block chains are being filtered out. With 5% hashpower, an attacker could do it in a reasonable amount of time.

No. Try to solve a block by yourself with your PC. It will take years. You cannot change the difficulty of the blockchain even if you MITM

I understand that the difficulty is not changing. An attacker can own more than one PC, for example if one of the top 10 mining pools in China decides to perform this attack, or gets compromised by a hacker.