rich1.0Braydon Fuller [ARCHIVE] (npub1fx…xxtaa)https://nostr.ae/npub1fx2eyw7avet7dut0slazcehwvrrlhjp2u9jc9zd92l7nexpxeahs4xxtaanjumphttps://nostr.ae📅 Original date posted:2019-10-04 📝 Original message:On 10/4/19 1:20 AM, David A. Harding wrote: > On Thu, Oct 03, 2019 at 05:38:36PM -0700, Braydon Fuller via bitcoin-dev wrote: >> This paper describes a solution [to DoS attacks] that does not >> require enabling or maintaining checkpoints and provides improved security. >> [...] >> The paper is available at: >> https://bcoin.io/papers/bitcoin-chain-expansion.pdf > [..] But I worry that the mechanisms could also be used to keep a node that > synced to a long-but-lower-PoW chain on that false chain (or other false > chain) indefinitely even if it had connections to honest peers that > tried to tell it about the most-PoW chain. Here is an example: An attacker eclipses a target node during the initial block download; all of the target's outgoing peers are the attacker. The attacker has a low work chain that is sent to the target. The total chainwork for the low work chain is 0x09104210421039 at a height of 593,975. The target is now in the state of a fully validated low work dishonest chain. The target node then connects to an honest peer and learns about the honest chain. The chainwork of the honest chain is 0x085b67d9e07a751e53679d68 at a height of 593,975. The first 69,500 headers of the honest chain would have a delay, however the remaining 52,4475 would not be delayed. Given a maximum of 5 seconds, this would be a total delay of only 157 seconds.