Author: Matt Corallo 2017-03-22 21:51:08
Published on: 2017-03-22T21:51:08+00:00
The Bitcoin blockchain is at risk of being attacked by miners using oversized blocks to force a hard fork, which could be proven. Users who do not use their own full node for validation may need protection from these attacks to ensure they remain on the Bitcoin blockchain. Luke Dashjr has written a draft BIP for fraud proofs and how light clients can detect blockchains that are invalid due to excess size and/or weight. This draft may be ready for implementation, but suggestions are welcome for improvement. The key observation is that all you need to show the length and hash of a transaction is the final SHA256 midstate and chunk, which can prove the exact size of a transaction. A valid transaction must be at least 60 bytes long for compression. However, much of the compression possibility goes away if you're proving something other than "too large". It is ideal to have an extension to SPV protocol so light clients require proofs of blocks not being too big, given the credible threat of there being an extremely large-scale attack on the network of that form.
Updated on: 2023-05-20T01:05:41.940071+00:00