It is a decade since August 15th, 2010, the day in which a person took advantage of a bug in the Bitcoin (BTC) code to create 184,467 million BTC. The cryptocurrency, which was one year and eight months old, was still in its infancy. During those years, Satoshi Nakamoto, and his collaborators worked many times by trial and error, so that Bitcoin met the high standards that they imposed themselves.
The means of communication they used between them was the Bitcointalk forum. That Sunday in August, Jeff Garzik, who helped develop Bitcoin from the early years, wrote there: “The exit value at block 74,638 is quite strange.”
It is that the block showed that, for 1 hour and a half, there were outputs that reached a total of 184,467 million BTC. This is a value of almost 8,800 times higher than 21 million, which is the maximum supply set for this cryptocurrency.
What could have happened?
Another user of the forum, under the pseudonym “LFM,” explained what happened. He said that a person made a custom modification of the software to generate a transaction that exploited vulnerability in the code and artificially inflate the supply.
The code used to verify the transaction before, including it in the block, did not contemplate the case that the outputs were so large that they got excessive when added.
LFM added to its explanation of this weakness of the program that the code checked the output of each transaction for numbers individually, but “forgot” to check whether the sum of two outputs resulted in a negative number.
Therefore, if two significant but positive values got a place in the transaction, the overflow was only checked if it was less than or equal to the inputs. Thus, it was possible to issue several coins that excessively inflated the supply.
A solution in record time
Soon, Nakamoto and developer Gavin Andresen began working to fix what happened. Just 2 hours and 21 minutes after Garzik made the announcement, they released a patch for the code that fixed this problem in future transactions. An hour later, the spot saw an upload to the repository. The role was to reject outbound overflow transactions, like the one that had got made, and also any transaction that pays more than 21 million BTC in a single exit.
The solution was a soft fork of the blockchain whereby the problematic transaction and all subsequent transactions found a reversion. The miners accepted the proposal, and the new blockchain surpassed the old one at block 74,691, nineteen (19) hours after the incident. The ideals of immutability were momentarily set aside for the greater good and long-term benefit to the community.
Currently, there is no malicious transaction or the BTC created, although the 0.5 BTC it consumed does. They have not used this according to the Bitcoin wiki; they appear to come from a faucet. This was the only major security flaw found until now in the entire history of Bitcoin. To date, the first cryptocurrency had 48 vulnerabilities detected, although none as serious as this one.
All Miners Should Stop Processing Transactions until a Solution Appears
A few days before the four months of the incident mentioned here, Nakamoto published his last message on Bitcointalk. It was a fix to prevent denial of service (DoS) attacks.
After that, the creator of Bitcoin disappeared from the public scene, and, since then, his identity is the subject of speculation worldwide.
Furthermore, it was a suggestion that all miners stop processing transactions until a solution appears. It was requested to ignore the block in which the error occurred and all subsequent blocks.
By Jenson Nuñez
