{"type":"rich","version":"1.0","author_name":"Braydon Fuller [ARCHIVE] (npub1fx…xxtaa)","author_url":"https://nostr.ae/npub1fx2eyw7avet7dut0slazcehwvrrlhjp2u9jc9zd92l7nexpxeahs4xxtaa","provider_name":"njump","provider_url":"https://nostr.ae","html":"📅 Original date posted:2019-10-04\n📝 Original message:On 10/4/19 1:20 AM, David A. Harding wrote:\n\n\u003e On Thu, Oct 03, 2019 at 05:38:36PM -0700, Braydon Fuller via bitcoin-dev wrote:\n\u003e\u003e This paper describes a solution [to DoS attacks] that does not\n\u003e\u003e require enabling or maintaining checkpoints and provides improved security.\n\u003e\u003e [...] \n\u003e\u003e The paper is available at:\n\u003e\u003e https://bcoin.io/papers/bitcoin-chain-expansion.pdf\n\u003e [..] But I worry that the mechanisms could also be used to keep a node that\n\u003e synced to a long-but-lower-PoW chain on that false chain (or other false\n\u003e chain) indefinitely even if it had connections to honest peers that\n\u003e tried to tell it about the most-PoW chain.\n\nHere is an example: An attacker eclipses a target node during the\ninitial block download; all of the target's outgoing peers are the\nattacker. The attacker has a low work chain that is sent to the target.\nThe total chainwork for the low work chain is 0x09104210421039 at a\nheight of 593,975. The target is now in the state of a fully validated\nlow work dishonest chain. The target node then connects to an honest\npeer and learns about the honest chain. The chainwork of the honest\nchain is 0x085b67d9e07a751e53679d68 at a height of 593,975. The first\n69,500 headers of the honest chain would have a delay, however the\nremaining 52,4475 would not be delayed. Given a maximum of 5 seconds,\nthis would be a total delay of only 157 seconds."}