Everyone Says Bitcoin Has Been Decentralized Since Block Zero. Block 74638 Says Otherwise.

Written by Marlowe Finch, archival bloodhound at Bitcoin Institute. Bitcoin has been decentralized and trustless since block zero. No CEO, no committee, no kill switch, no single person who can rewrite the rules. That's the pitch. It's why the whitepaper still gets quoted like scripture. Block 74638 does not agree with the pitch. What actually shipped in that block On August 15, 2010, a transaction landed in the Bitcoin blockchain with two outputs. Each one paid out 92,233,720,368.54277039 BTC . Combined: over 184 billion BTC — roughly nine thousand times the 21 million BTC that will ever exist, created in a single transaction. The validation code, CheckTransaction() , checked that each individual output was non-negative. It never checked whether the sum of the outputs overflowed. Two values chosen just under INT64_MAX, added together, wrapped around to a negative number in signed 64-bit arithmetic. A 0.5 BTC input, compared against that negative sum, satisfied the "input covers output" check. The transaction validated. The block got mined. Every rule the network was running said this was fine. That's CVE-2010-5139. It is also, by any dollar value you want to apply, the most expensive missing bounds-check ever shipped to production. So who hand-builds a transaction engineered to overflow a signed 64-bit integer, and what does a currency with a hard 21-million-coin cap do when someone mints nine thousand times that in one block? The archive's full account of the incident lays it out block by block . The receipts 18:08 UTC, August 15 — Jeff Garzik opens a BitcoinTalk thread titled "Strange block 74638", pastes the raw block dump, and closes with one question: "92233720368.54277039 BTC? Is that UINT64_MAX, I wonder?" 20:38 UTC — Satoshi Nakamoto, to the bitcoin-list mailing list, network-wide: "*** WARNING *** We are investigating a problem. DO NOT TRUST ANY TRANSACTIONS THAT HAPPENED AFTER 15.08.2010 17:05 UTC (block 74638) until the issue is resolved." 20:39 UTC — Ga