In the digital currency field, Bitcoin has always been the focus of much attention. Recently, Core developers have proposed an exciting news: Bitcoin development has made new progress, which can better conduct private transactions. This news will undoubtedly cause a sensation in the digital currency community. Let's take a deep look at this important development.

As the digital currency market continues to develop, privacy issues have always been a hot topic. As one of the most well-known cryptocurrencies, Bitcoin's privacy has always been controversial. The new progress of Core developers will bring new possibilities for Bitcoin's private transactions, allowing users to trade more safely and conveniently.

In the past few years, privacy coins have gradually emerged in the digital currency field. The rise of privacy coins such as Monero and Zcash has made people realize the importance of privacy in digital currency transactions. As the digital currency with the highest market value, Bitcoin's improved privacy will set a new benchmark for the entire industry and provide users with a safer trading environment.

How will the new plan proposed by Core developers affect the future development of Bitcoin? First, this progress will strengthen the privacy protection mechanism of the Bitcoin network and provide users with a more anonymous trading experience. Secondly, the improvement of private transactions will attract more users to participate in Bitcoin transactions and promote the further development of the digital currency market. Most importantly, the improvement of privacy transactions will lay a solid foundation for the long-term stable growth of Bitcoin.

With the continuous evolution of the digital currency market, privacy has become one of the important considerations for users to choose digital currency. As the digital currency with the highest market value and the greatest influence, the improvement of Bitcoin's privacy will lead the entire industry to a safer and more convenient direction. The new progress of Core developers has injected new vitality into Bitcoin and made people full of confidence in the future of digital currency.

In general, the new progress of Bitcoin has brought about another upgrade of privacy transactions and injected new vitality into the digital currency market. As Core developers continue to work hard to improve the Bitcoin network, I believe that in the near future, Bitcoin will become a more secure and more private digital currency, bringing users a better trading experience. Let us wait and see, and witness the brilliant future of Bitcoin together!

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Bitcoin Core developer Amiti Uttarwar is working on modifying Bitcoin's network replay logic to introduce more privacy during transaction replay.

Image credit: Pixabay

Uttarwar is a relatively new member of the Bitcoin Core team, having first been hired as a Bitcoin Core developer at cryptocurrency startup Xapo in October 2019. Her main focus now is a proposed change to Bitcoin's replay logic, which Bitcoin Core developer Pieter Wuille has previously highlighted as one of many promising peer-to-peer implementation projects.

As Uttarwar explained in a September 2019 talk, when a user initiates a Bitcoin transaction, they need to broadcast the transaction - meaning they have to send an INV message to other nodes and make sure the transaction is in everyone else's memory pool.

However, the initial broadcast doesn't always go through successfully. For example, there could be a problem with the relay process, or the transaction could be pulled from the memory pool when other transactions pay a higher fee. If such a problem occurs, the user would have to send another INV message and rebroadcast it to other nodes.

Explaining the motivation for the replay change, Uttarwar said: “The current replay logic is horrible for privacy.”

How the change works

Under the current system, she said, only the source wallet rebroadcasts transactions. As a result, if a spy node sees two INV messages for the same transaction from the same node, it can infer that the node is the source wallet, “and the privacy of the transaction is broken.”

“This leaves room for a kind of dusting attack vulnerability,” she said. Dust attacks occur when an attacker sends small amounts of BTC to many different addresses and observes the replay behavior of various wallets, thus destroying the privacy features of the network.

The mechanism proposed by Uttarwar would mitigate this vulnerability by having a more private replay behavior that does not reveal the source wallet of the transaction. If the Bitcoin network implemented her proposed alternative design, all nodes would replay the replays they believe “should have been confirmed” instead of just the replays sent by the source wallet.

“I pulled the logic out of the wallet and into the node and used a block assembler so that we can identify the top of the mempool in a similar way to how the node sees it,” she said. “I updated the wallet logic to resubmit unconfirmed transactions to the node instead of sending them directly to other nodes. I added a recency filter to the block creation logic so that we can ignore recent transactions.”

Development Path

This pull request (PR) was first opened in August 2019, and Uttarwar told The Block that she has made considerable changes to the proposal since then.

“One of the biggest changes is that I have been able to break out the functionality of the large PR into a standalone change. So I am currently working on implementing that transition. Once we merge it, I will return to this larger rebroadcast project.”

Another major change involves a mechanism that tracks the maximum amount of time a person can rebroadcast a transition. While Uttarwar had previously planned to make this a follow-up to her rebroadcast proposal, she recently decided not to build it after auditors highlighted how the lack of this change could make it an attack vector.

Uttarwar also pointed to excessive bandwidth usage as one of the potential issues behind her design choices.

“I think bandwidth is something we should think about carefully, and if we do it wrong, it could be problematic,” she said.

To avoid extreme network-wide bandwidth spikes, Uttarwar has implemented some preventative mechanisms, including Poisson distribution of replay timing for each node and filtering logic for replay candidates.

The PR has been in the works for seven months, but she said she is in no rush to push the proposal through.

“I’m less concerned about timelines and more about robustness at each step,” she said. “I don’t want anything to be merged too early.”