Bitcoin double spend

This doesnt look sinister. (Updates blockchain description, starting in the fourth paragraph.). Other cryptocurrencies also sold off, with the Bloomberg Galaxy Crypto Index losing as much. However, many people were still curious what the nature of the different transactions published by Alice was. Bob wont get his funds. Opens in a new window Opens an external site Opens an external site in a new window.

The attacker now has 1m in ETC plus 1m in BTC. There are two popular definitions for what a double spend is, a technical and a practical one. This is almost certainly what happened with Alices replacement transactions 2 and 3 (more on that in the Addendum). On January 22, 2021, the Fork Monitor feature on BitMEX appeared to indicate that a double-spend had happened. As Bitcoin engineer and researcher 0xB10C shows in this diagram, a user (lets call her Alice) broadcasted three competing transactions, each of them updating the fee rate compared to the previous one. Its like if someone bought a car, paid the seller, drove off with their brand new wheels and then later yanked back all the money.

What is a double-spend? BitMEX tweeted what it believed had occurred, and the crypto press immediately leaped on the news. Our miner broadcasts their block to all the other miners on the network, bitcoin double spend who all confirm that the transactions in the block are valid based on the current state of the blockchain. Why did the lower fee transaction (1 sat/b) win? Our miner adds their block of transactions to the blockchain and receives their mining rewards in bitcoin.

Bitcoin Double-Spend: The Reason Behind the BTC Crash

Here are some useful heuristics for when you should panic: The value of the invalidated transaction is in the tens to hundreds of millions of dollars. Merchants often wait for a payment to be verified as many as six times. However, it has occurred on other networks, such as Ethereum Classic. Transactions are entered on the blockchain after an unaffiliated third party verifies the deal, often in exchange for partial coins.

This leaves only the second output of transaction 1, 3JaLvP to bitcoin double spend be unaccounted for. Rational miners tend to fill their blocks to the brim with the highest paying transactions because that gives them the most profit. Uncooperative closes have hard deadlines, and missing that deadline because of insufficient fees could result in a loss of funds for users. For more articles like this, please visit us at m 2021 Bloomberg.P.

Occasionally, two miners will simultaneously solve the proof-of-work puzzle, resulting in two separate versions of the blockchain where miners must decide which version they wish to continue mining. As well now see, there are good reasons for a Bitcoin user to broadcast such conflicting transactions.


We're No.1 manufacturer in the field of the Electric Wire and Cable in Laos. Its quality has been recognized by both the public and the private sectors for more than 20 years, and manufacturing facilities are certified to the ISO 9001 quality standard.

Contact Us

Opening Hours

Monday 08:00 - 17:00
Tuesday 08:00 - 17:00
Wednesday 08:00 - 17:00
Thursday 08:00 - 17:00
Friday 08:00 - 17:00
Saturday 08:00 - 17:00
Template Settings


For each color, the params below will give default values
Orange Green Red Cyan Blue


Background Color
Text Color


Background Color


Select menu
Google Font
Body Font-size
Body Font-family