Would quantum computing be able to deanonymize CoinJoin transactions?

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Andrew Poelstra is a mathematician at Blockstream and was recently part of a panel discussion on improvements for Bitcoin at the 2016 MIT Bitcoin Expo. During the panel, Poelstra discussed Confidential Transactions, which is a privacy-enhancing feature he has been working on with Blockstream co-founders and Bitcoin Core contributors Greg Maxwell and Pieter Wuille.

One of the main reasons Blockstream is working on Confidential Transactions is to preserve the censorship-resistant properties of Bitcoin and other blockchains.

Scalability Is Not the Only Problem with Bitcoin

Although scalability solutions have been a major area of contention lately, Poelstra understands this is not the only real problem. During his recent appearance at the MIT Bitcoin Expo, Poelstra pointed out the issues related to the public nature of Bitcoin transactions:

“Lately, we’ve been talking about scaling and centralization, but that’s not the only problem with Bitcoin. This one...

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From bitcoin to blockchain to distributed ledgers, the cryptocurrency space is fast evolving, to the point where it can be difficult to see in which direction it's headed.

But, we're not without clues. While many of the innovations in the space are new, they're built on decades of work that led to this point. By tracing this history, we can understand the motivations behind the movement that spawned bitcoin and share its vision for the future.

Before the 1970s, cryptography was primarily practiced in secret by military or spy agencies. But, that changed when two publications brought it into the open: the US government publication of the Data Encryption Standard and the first publicly available work on public-key cryptography, "New Directions in Cryptography" by Dr Whitfield Diffie and Dr Martin Hellman.

In the 1980s, Dr David Chaum wrote extensively on topics such as anonymous digital cash and pseudonymous reputation systems, which he described in his...

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Can we integrate Tor into breadwallet?

This is a fairly obvious request and one that I feel must have been suggested before. But, upon a cursory glance, I do not see this officially suggested nor debated!

SPV is great, but the downside is that random nodes from the Bitcoin network are contacted to propagate payments. These nodes may be benign or malicious, SPV does not know (and until the latest update of breadwallet addressing tarpit nodes, it did not distinguish good from bad). Besides stalling transactions, nodes may surveil the network and attempt to build profiles via IP addresses, among other information. To hinder that surveillance, increase privacy of breadwallet users, and thereby increase the integrity of the Bitcoin ecosystem, I think it is high priority to integrate Tor (or something else as effective, but Tor seems by and large the most recommended and vetted) in a seamless, secure, and automatic manner.

Adding further in the vein of...

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Can/Could vs Be Able To

There is a huge interest in the difference between can or could and be able as can or could and be able to are two different usages made in the English languages and they both carry different senses with them. Can or could and to be able to are all verbs. Can is the present tense of could and could is the past tense of can. To be able to is a different verb. However, one can see that the use of can or could in the English language is much more common than the use of the verb be able to.

What does Can or Could mean?

Can is used to indicate the idea of possibility as in the sentence given below.

I can do the work.

This only gives the idea that ‘it is possible for me to do the work’. The same is true even in the case of could.

On the other hand, could is generally used as a past tense form of can as in the sentence mentioned below.

I could go.

This sentence means ‘it was possible for me to go’....

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Quantum computers, first theorized by physicist Richard Feynman in 1982, have promised a new era of computing. The theory has only recently translated into significant real-world advances, with NASA, the CIA and Google working on a quantum computer. Computer scientists now warn the machines will cripple existing encryption methods and destroy bitcoin’s technological foundations.


Quantum computing studies theoretical computation systems (quantum computers) that make direct use of quantum-mechanical phenomena, such as superposition and entanglement, to perform operations on data. Quantum computers are different from binary digital electronic computers based on transistors. Whereas common digital computing requires that the data be encoded into binary digits (bits), each of which is always in one of two definite states (0 or 1), quantum computation uses quantum bits, which can be in superpositions of states. A quantum Turing...

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Quantum computers are computers which exploit quantum mechanics to do certain computations far more quickly than traditional computers. A sufficiently large quantum computer would cause some trouble for Bitcoin, though it would certainly not be insurmountable.

Note that the abbreviation QC can stand for either quantum computer(s) or quantum cryptography.

QC attacks

The most dangerous attack by quantum computers is against public-key cryptography. On traditional computers, it takes on the order of 2128 basic operations to get the Bitcoin private key associated with a Bitcoin public key. This number is so massively large that any attack using traditional computers is completely impractical. However, it is known for sure that it would take a sufficiently large quantum computer on the order of only 1283 basic quantum operations to be able to break a Bitcoin key using Shor's Algorithm. This might take some time, especially since the first quantum computers are...

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This is a Trial Version of Social Share & Locker Pro plugin. Please add your purchase code into Licence section to enable the Full Social Share & Locker Pro Version.

There has been a lot of talk about Bitcoin and whether or not it is anonymous. Cryptocurrency experts will gladly point out Bitcoin is not anonymous, but rather pseudonymous. For those people interest in de-anonymizing cryptocurrency, however, BitCluster is a solution looking into. This tool has now been open sourced, and users can download the kit, as well as the database, from the website right now.

Explaining what BitCluster does, it’s not overly difficult, as this open-source tool is designed to analyze Bitcoin transactions. Moreover, this tool can also regroup Bitcoin wallet addresses based on their incoming and outgoing transactions. All of this information is taken from the blockchain, which is available to the public in real-time.

Should BitCluster Be Trusted?


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Although bitcoin is famous for its anonymity level, it is agreed that it is not completely anonymous as there are multiple ways for tracking the sender of bitcoin transactions in most cases. We will discuss the Bayesian method for identification of bitcoin addresses throughout this article.

The Bayesian method for identification of bitcoin addresses can be broken down into 3 main steps:

1- Identification of the IP addresses linked to transactions in question

2- Categorization of bitcoin addresses

3- Assigning bitcoin addresses to users.

First, messages propagating across the bitcoin network are recorded and observed via special monitoring clients so that the greatest possible part of the network could be covered. These clients get information from the senders of transactions before being relayed onto the first time segment. After some analysis, more attention is directed towards the monitoring clients that are likely to be the originator...

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Will quantum computing undermine the security of cryptocurrencies like Bitcoin?

A Quantifiable Risk

Quantum computers, for all of their press, will not be used in everyday applications such as running word processors or playing games. Rather, they will help with large data processing tasks and problem solving. However, while most individuals on this planet only have positive intentions for such inventions, there are others who have malicious intentions.

Quantum computers have an incredible ability to perform multiple calculations simultaneously, unlike conventional computers. For example, modern computers could never brute force hack a 256-bit key by going through every combination whereas a quantum computer could achieve this with ease.

To put the speed difference into perspective, Google's D-Wave 2X quantum computer can solve algorithms 100,000,000 faster than modern computing devices. This means that brute force attacks on security protocols will...

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Right now, quantum computers cost millions of dollars and are only used by governments and big data companies. But as the tech becomes more widely available, will quantum computing be able to hack even the most secure algorithms, like Blockchain?

Quantum computing won't be hacking Blockchain algorithms.Click To Tweet

A Million Times More Powerful

Quantum computers have the potential to map proteins, analyze entire genomes, and behave more intuitively than today’s conventional computers. Why wouldn’t they be able to bust Blockchain?

Blockchain is a public ledger of all bitcoin transactions that have ever been executed. The public record is constantly growing with each bitcoin transaction, and it is chronological.

Quantum computation does not store information using 0s or 1s, also known as bits, like conventional computers.

Instead, they use quantum bits, or qubits, to encode information as 1s or 0s or both at the same time.


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DEFINITION of 'Coinjoin'

An anonymization strategy that protects the privacy of Bitcoin users when they conduct transactions with each other. Coinjoin requires multiple parties to jointly sign on an agreement to mix their coins when engaging in separate Bitcoin transactions.

Also known as Coin Mixing.


Advancements in technology are introducing digital tools that companies can use to better interact with their customers. A rising shift from traditional platforms to digital platforms has also brought about an abundant supply in data from sources like social media, mobile devices, online retail platforms, etc. Due to technology advancements in the areas of gathering, storing, and sharing data, large sets of data are easily shared among companies in every sector and country for little to no costs. The widespread accessibility of data has also brought about concerns over data privacy of individuals and their online transactions....

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Researchers in Russia say they've developed and tested the world's first blockchain that won't be vulnerable to encryption-breaking attacks from future quantum computers.

If the claims are verified, the technique could be a means of protecting the vast amounts of wealth invested in fast-growing cryptocurrencies like Bitcoin and Ethereum – which are safe from today's code-breaking methods, but could be exposed by tomorrow's vastly more powerful quantum machines.

A team from the Russian Quantum Centre in Moscow says its quantum blockchain technology has been successfully tested with one of Russia's largest banks, Gazprombank, and could be used as a proof of concept to underpin secure data encryption and storage methods in the future.

To backtrack a little, a blockchain is a publicly accessible, decentralised ledger of recorded information, spread across multiple computers on the internet.

This kind of distributed database is the underlying technology that...

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A guide to solving intractable problems simply

Brad Huntting and David Mertz
Published on September 01, 2001

Alan Turing invented the programmable computer in 1936 (see Related topics) as a thought experiment to show that certain mathematical problems were not computable. Implicit in his argument was the idea that a computer, armed with sufficient resources, is capable of realizing any reasonable algorithm.

Since that time, the computer industry has not only managed to build programmable computing machines, they've also outdone themselves by doubling the capabilities every eighteen months or so. Despite these frenetic advances in computer technology, modern computers are still unable to make significant dents in hard problems. Problems that require exponential resources (compared to the size of the problem itself), remain as intractable today as they were in 1936.

In 1982 Richard Feynman suggested that the venerable...

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Drew Cordell · October 6, 2015 · 8:00 am

A team of engineers from the University of New South Wales has developed a device that allows two quantum bits, known as qubits, to communicate with one another, this brings the world one step closer to quantum computing. The device achieves communication of two qubits with silicon. Binary bits take a state of either 0 or 1. In a quantum computer, qubits can assume a state of 0,1 or both at the exact same time. In theory, the ability for a qubit to be both at the same time allows the computer to make many computations in parallel at incredibly fast speeds.

Also read: Bitcoin Is Superior To Cashless Systems Used Today

Quantum operations need to be...

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There’s been no shortage of innovative ideas across the Internet in recent years. Some of them, including BitCoin and Off-the-Record Messaging, rely on Public-key cryptography to guarantee ultimate secrecy and complete authenticity.

Unfortunately for services that use Public-key cryptography, Quantum computers, systems that perform operations on data at unimaginable speeds, are on the rise and being used to make important breakthroughs, particularly in science. For companies like BitCoin however, Quantum computers are a frightening prospect and potentially detrimental to their longevity.

The Guardian recently released an article stating that the progress seen in Quantum computing was beneficial for science. Canadian company, D-Wave, used a Quantum computer to work out how protein folds. Due to the complexity of D-Wave’s discovery, there were even claims from scientists that their findings were so advanced that they couldn’t possibly be true, a sentiment that was...

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Andrew Poelstra (andytoshi) Pieter Wuille (sipa) Brian Deery Chris Odom

Starts at 26min.

I am going to introduce our guests here in just a minute.

Launch of zcash might be delayed in order to allow the code to be analyzed by multiple third-party auditors. Zooko stated, "I feel bad that we didn't do a better job of making TheDAO disaster-like problems harder for people".

Our guests on the line are Andrew Poelstra and Pieter Wuille. Andrew are you there?

AP: Hey. We're here.

host: I am going to let you guys give our audience some background. Andrew, tell us about yourself and what you do i nbitcoin.

AP: Sure. I showed up in the bitcoin space around late 2011 while I was starting a PhD in mathematics. I wound up hanging around on the research side of things, like IRC channels centered on cryptography research. These days I work on the...

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