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Simplified Payment Verification Revisited

links: DSS TOC - Evolving the Protocol - Index

The Activation of BIP-66 (Bitcoin Improvement Proposal) lead to an unexpected behaviour after a not upgraded miner mined an invalid block (which was expected by the change). A significant percentage of upgraded miners did then build on top of the invalid block. This led to an invalid chain of 6 blocks, which eventually died. The problem is that during the time this chain existed, SPV Nodes were vulnerable because full nodes processing the wrong chain gave invalid Merkle Proofs to the SPV Nodes which should not have been given to them. This made it visible that trusting miners (full nodes) was a bad idea. This showed that Bitcoin can only be secure if block verification is sufficiently easy.

links: DSS TOC - Evolving the Protocol - Index