Se corrió la voz en twitter y reddit que la semana pasada, después de la actualización planificada a la red de Bitcoin Cash, un minero desconocido intentó usar un exploit para reclamar monedas que se suponía que eran insostenibles. Cuando los grupos mineros BTC.COM y BTC.TOP vieron esto, trabajaron juntos, controlando más de la mitad de la red, para realizar un ataque del 51% y reorganizar los bloques recientes para reclamar los fondos. Ahora la comunidad está comprensiblemente molesta, ya que esto destruye completamente la noción de “descentralización” en la red.
Bitcoin Cash (BCH) has experienced a coordinated 51% attack. https://t.co/AEeyOVaWM4
— Bitcoin Magazine (@BitcoinMagazine) 24 de mayo de 2019
La historia es un poco complicada, pero Guy Swann hizo todo lo posible por explicar la situación en Twitter, aquí hay algunos puntos destacados:
‼️#BCH /#bcash was hit by 51% attack from just 2 miners, https://t.co/gZNf6P1G3l & https://t.co/2gkV6KUcCt
— Guy Swann⚡ (@TheCryptoconomy) 24 de mayo de 2019
– & no one seems to be talking about it. 🤨
Thread 👇🏻
1/ What I've gathered from loose details:
First, there was an unintentional split with the recent #BCH "upgrade."
2/
— Guy Swann⚡ (@TheCryptoconomy) 24 de mayo de 2019
Since the original split in 2017, there has been a significant number of coins accidentally sent to "anyone can spend" addresses (due to tx compatibility of sigs, but no #SegWit on #BCH), or possibly they've been replayed from #Bitcoin onto the #BCH network.
3/
— Guy Swann⚡ (@TheCryptoconomy) 24 de mayo de 2019
Because of this, tons of coins (#BCH) would essentially be "up for grabs." However, devs implemented a protocol rule called CLEANSTACK, making P2SH coins unspendable.
This was to be removed with May 15 fork, basically handing the coins to miners.https://t.co/ITT9djMSSo
4/
— Guy Swann⚡ (@TheCryptoconomy) 24 de mayo de 2019
During the unintentional fork, someone exploited a bug (details are really hard to find) to add invalid TXs to @Bitcoin_ABC's client mempool.
To counter, https://t.co/gZNf6P1G3l mined empty blocks (the bad TXs made blocks impossible to produce)https://t.co/VyDq1RpBOS
5/
— Guy Swann⚡ (@TheCryptoconomy) 24 de mayo de 2019
Due to low hash rate of the network, https://t.co/gZNf6P1G3l actually controlled over half (~54%) of #BCH hash power. Putting them in a position to essentially dictate which blocks were accepted by the network.
(we'll see the problem here in a sec)https://t.co/1lZEuO5GA9
6/
— Guy Swann⚡ (@TheCryptoconomy) 24 de mayo de 2019
In the confusion, an unknown miner (possibly the attacker, but unconfirmed) tried to snatch a bunch of P2SH/#Segwit coins. But https://t.co/gZNf6P1G3l & https://t.co/h08wTM6XgZ were expecting, and/or preparing to recover SegWit coins themselves…https://t.co/jNzqgOh4km
8/
— Guy Swann⚡ (@TheCryptoconomy) 24 de mayo de 2019
When the unknown miner tried to take the coins themselves, https://t.co/gZNf6P1G3l & https://t.co/h08wTM6XgZ saw & immediately decided to re-org & remove these TXs, in favor of their own TXs, spending the same P2SH coins, + many others.https://t.co/jNzqgOh4km
13/
— Guy Swann⚡ (@TheCryptoconomy) 24 de mayo de 2019
There are at least a few people (maybe only partially) realizing that this basically kills any perception that #BCH is "decentralized, censorship resistant money." And leaves them to fight over whether the miners are "good guys" or "bad guys" with their actions. pic.twitter.com/zKR1sc19ux
El hilo enlaza a un blog que parece ser del atacante, explicando por qué hicieron lo que hicieron.
Esta noticia ha pasado por el radar para muchos, pero algunos en Twitter definitivamente están formando opiniones sobre esto:
HAHA LOL…..Just buy BTC.
— JSTRECKT (@mikel420) 24 de mayo de 2019
Evidence that PoW can be manipulated. The real question is since it was BCH does that mean BTC can be manipulated in the same way. Block reorgs seem to be a hot topic lately and was successfully pulled off by BCH miners.
— BInfinent (@BInfinent) 24 de mayo de 2019
En última instancia, depende de cada usuario si se sienten cómodos con solo dos mineros que tienen suficiente poder para reorganizar la cadena de bloques, pero parece que esto es definitivamente lo que sucedió. BTC.TOP tuvo en el pasado más del 51% del poder de hash por sí solo, aunque recientemente este número ha disminuido.
