This is partly why I am concerned anytime I read about internet traffic getting routed through China temporarily in “error” as the Chinese government can capture the encrypted traffic and potentially decrypt it once they develop the technology to do so.
Bit of an aside, but China are probably the world leaders in quantum cryptography (using quantum mechanics to build quantum-safe solutions that are fundamentally unhackable due to the laws of physics). Have a look at their work with Micius, part of their QUESS (Quantum Experiments at Space Scale) project. They have already demonstrated quantum key distribution (QKD) wirelessly via satellite, generating a pair of entangled photons using an interferometer. Their aim is to have a global quantum network in place by 2030... ... and if they are that far ahead of the game here, I certainly wouldn't bet against them being first to develop a proper QC capable of real-world decryption.  https://www.sciencemag.org/news/2017/06/china-s-quantum-satellite-achieves-spooky-action-record-distance |
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the difficult part is dealing with the 5+ million vulnerable coins (p2pk outputs, outputs sitting in reused addresses, shared xpubs, etc). implementing a post-quantum signature scheme alone doesn't address the fact that 1/3 of the supply is vulnerable to theft. people need to voluntarily move their coins to quantum-safe addresses for the fork to be effective. that could take a few years, based on the adoption rate of segwit.
Indeed. The question of what to do with the coins that are not moved to quantum-proof addresses is a huge problem. From my amateurish perspective, it seems to me that if the problem couldn't be solved in time, and it came to a choice between either (a) burning anything that hasn't been moved, or (b) leaving them there to be scooped up by a QC ... then I think option (a) is far preferable. You can't just soft-fork to a situation where some bitcoins are quantum resistant and some aren't; (b) could lead to another gox or worse. A hard-fork option (a) would still be hugely contentious but if it comes down to a question of bitcoin's survival, it's the better option. Either way you're never going to get a consensus, and there would likely be a serious* chain-split. *serious, not like BCH. |
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the undeniable fact is that at some point something will come along (either out of the blue and shock us all or by virtue of a slow build up) to pose a serious threat to private keys.
Yes, perhaps. This is an important point to consider, and I do have a favoured approach which I'll get to in a moment. Public key cryptography is insecure against a QC running Shor's alogrithm, whilst certain symmetric systems such as AES256 do seem quantum secure against the best QC attack (Grover)... and this holds no matter how many qubits you throw at it. The key point in any cryptography is that it may be secure now, and it may be secure against such future technological or mathematical advances as we can envisage, but how can we ever say it's secure against such future technology as we can't even conceive right now? At first glance it seems we can never provide that absolute certainty. However I believe we can get close. This is where we have the distinction between post-quantum cryptography, which involves using classical computers to devise quantum-proof systems and algorithms, and quantum cryptography, which uses the laws of quantum mechanics to build a defence. You will be aware of the Schrodinger's Cat thought experiment, where the cat is neither alive nor dead until it is observed, existing instead in a hybrid state, a superposition of both classical outcomes. Whilst this may be an absurd extension of the quantum realm into the macroscopic, it certainly holds true on a quantum level. The act of observation collapses the wave function and forces an outcome. This is an immutable physical law. And if we then combine this with quantum entanglement, this enables key sharing that in theory is immune to hacking or eavesdropping, because any attempt by a third party to intercept the key collapses and invalidates the whole thing. I'll go into it in more depth if the thread heads that way... |
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For Bulletproofs, what matters is the Shor RSA2048 line, which is predicted to be broken in 2022–23. In fact, ECC is more vulnerable than RSA in a post-quantum world, so our discrete logarithm assumption may be broken even sooner. Whilst it's true that ECC is more vulnerable than RSA, this is only a question of scale. With sufficient qubits, both can be broken, it's just that it takes more to break the equivalent RSA. The problem here is that ECC and RSA are both asymmetric approaches. A symmetric approach such as AES256 offers far greater resistance. The difference between the two is the QCs best method of attack. For asymmetric cryptography, Shor's algorithm is the answer. For symmetric, Shor's approach doesn't work, and Grover's algorithm is the approach to use. And whilst Grover does reduce the difficulty somewhat, it is nowhere near as effective for symmetric systems as Shor is for asymmetric systems. I presented the numbers in a different thread, and can share if anyone is interested. |
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Hi, I summarised the threat of Quantum Computers (and some potential solutions) in another thread. Hope this answers the question and/or provokes further discussion. The weakest point with a QC attack is re-using addresses in a public-key (asymmetric) cryptographic system. The question of 'how soon' someone will have a sufficiently powerful QC is difficult to answer, given all the hype and bluster that accompanies each announcement, and also the distinction between 'proper' QCs and approaches that are merely quantum annealing, such as D-Wave. Hi all  I thought I’d try to summarise Bitcoin's vulnerabilities to Quantum Computers, as well as some potential defences, and get it all in one post. Apologies for the wall of text, but hopefully it is useful... Mining can potentially be much quicker with QCs.The current PoW difficulty system can be exploited by a Quantum Computer using Grover’s algorithm to drastically reduce the number of computational steps required to solve the problem. The theorised advantage that a quantum computer (or parallelised QCs) have over classical computers is a couple of orders of magnitude, so ~x100 easier to mine. This isn’t necessarily a game-changer, as this QC speed advantage is likely to be some years away, by which time classical computers will surely have increased speed to reduce the QC advantage significantly. It is worth remembering that QCs aren’t going up against run-of-the-mill standard equipment here, but rather against the very fast ASICs that have been set up specifically for mining. Re-used BTC addresses are 100% vulnerable to QCs.Address Re-Use. Simply, any address that is re-used is 100% vulnerable because a QC can use Shor’s algorithm to break public-key cryptography. This is a quantum algorithm designed specifically to solve for prime factors. As with Grover’s algorithm, the key is in dramatically reducing the number of computational steps required to solve the problem. The upshot is that for any known public key, a QC can use Shor’s approach to derive the private key. The vulnerability cannot be overstated here. Any re-used address is utterly insecure.Processed (accepted) transactions are theoretically somewhat vulnerable to QCs.Theoretically possible because the QC can derive private keys from used addresses. In practice however processed transactions are likely to be quite secure as QCs would need to out-hash the network to double spend. Unprocessed (pending) transactions are extremely vulnerable to QCs.As above, a QC can derive a private key from a public key. So for any unprocessed transaction, a QC attacker can obtain the private key and then create their own transaction whilst offering a much higher fee, so that the attacker’s transaction gets onto the blockchain first, ahead of the genuine transaction. So block interval and QC speed are both crucial here – it all depends on whether or not the a QC can hack the key more quickly than the block is processed. Possible defences... Defences using classical computers.- Modify the PoW system such that QCs don’t have any advantage over classical computers. Defending PoW is not as important as defending signatures (as above), because PoW is less vulnerable. However various approaches that can protect PoW against QCs are under development, such as Cuckoo Cycle, Momentum and Equihash.
- Modify the signature system to prevent easy derivation of private keys. Again, various approaches are under development, which use some pretty esoteric maths. There are hash-based approaches such as XMSS and SPHINCS, but more promising (as far as I can tell) are the lattice-based approaches such as Dilithium, which I think is already used by Komodo.
Defences using quantum computers.As I’ve said a few times, I’m more of a bumbling enthusiast than an expert, but exploiting quantum properties to defend against QC attack seems to me a very good idea. In theory properties such as entanglement and the uncertainty principle can offer an unbreakable defence. Again, people are busy researching this area. There are some quite astonishing ideas out there, such as this one. I’ll leave it there. Apologies for all the external links, but hopefully this has summarised a few things. |
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It is certainly better to sell whilst the coin is still rising. This sort of mega rise always continues too far and is followed by a big pullback. It happens absolutely every time, and the key is in judging the right moment to jump off.
Do be aware that however rapid the rise is, the fall is generally even quicker. It is very very easy to hold on too long and then discover that most of your gains have evaporated.
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retailers will no doubt start to experiment with alternatives to Visa.
I wasn't aware of the increase, but after a quick look I'm not sure it is enough of an increase to have that sort of effect. The increase seems to be from 1.9% to 1.99% ... but by comparison PayPal already charges 2.9% plus a small (30c / 30p) fixed amount. Perhaps they've just seen the amount that PayPal is taking, and that PayPal is still going strong, and so they are testing the waters with their own small increase. |
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It's certainly nice to see a pro-bitcoin candidate, and perhaps indicative of direction of travel, but really it's of zero relevance to the presidential race. Perhaps (probably) this will change in future elections as crypto moves inexorably into the mainstream, and the money involved snowballs to such an extent that it absolutely has to be addressed. At the moment however crypto is still small in terms of the US economy, and the question "What's your position on bitcoin?" is likely way way down the priority list of most voters. Indeed I would suspect that the way the candidates answer the question "Do you believe there's an all-powerful white-haired old man who lives in the clouds and created us and directs all of our actions?" has much more of a bearing on their popularity with voters.
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Ethereum has been under-priced for quite a while now. And as bitcoin rose recently, that obviously dropped the ETH price vs BTC even further. Eventually it had to reach a point where ETH became so much of a bargain that people started buying in... which has now happened.
And as we know, once people start buying a certain coin, it is very easy for the momentum to build and the coin to continue going up in price, which, again, is what we're seeing now.
As to what a reasonable value of ETH should be vs BTC, no-one knows, that's up to the markets to decide.
But to answer the question of whether ETH will hit a new ATH, yes, I think it will, just maybe not for a couple of years. It's unlikely this current rally will take it back over $1k.
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I anyone has the power to do this at the drop of a hat, it is China.
Drop of a bat is surely more topical for China? I really can't see a nation mounting a 51% attack. It would cost a hell of a lot of money for a start, and I don't see what they'd gain. If you want to shut down crypto within your own borders, then you can do this through legislation. It might not stop it entirely, but it would have a big enough effect to drive it so far underground that it's no longer a concern to the economy. Forcing exchanges to give out the details of their users for example, and then going after those users might be enough of a step by itself. The only reason for a nation to mount a 51% attack would be to shut crypto down entirely, globally. Whether that would be effective or not is difficult to say. Whether such an attack would be mounted however is maybe easier. I don't think there's much chance. The reason being that although crypto may cause some fear and concern for governments, it also offers the allure of huge benefits through increased efficiency, reduced costs and indeed surveillance through the immutability of the blockchain. Nations may posture and bluster about crypto being a problem, but I think the chances are everyone will adopt it in the end... and I think this conclusion is lent weight by the fact that more and more countries are now investigating the potential of digital versions of their national currencies, even the US is getting involved. |
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There has been a potentially important advance in qubit stability, published yesterday in Nature. Anyone with a passing interest knows that maintaining the qubit state is a big problem in quantum computing. The quantum system is quite fragile, and any interaction with the wider environment can cause the state to decohere ( decoherence meaning not actual wave function collapse, but rather the leaking of information across the boundary between the quantum system and its surroundings). There have been various attempts in the past to increase stability, some (such as magnetic containment) being more successful than others. The new experiment from the University of New South Wales uses quantum dots rather than normal silicon atoms, and they've built artificial atoms around these quantum dots - it's this approach that has increased the stability hugely. The problem with 'traditional' (I say traditional, but really QC is all quite new!) devices built on silicon atoms is that there are always atomic imperfections, which disrupt the qubits and lead to a high chance of decoherence. This new experiment removes the atomic nucleus entirely, and instead applies a voltage to pull in spare electrons to orbit the dot. This is then repeated until the inner electron shells have formed. So instead of a normal atom, with a nucleus surrounded by spherical electron shells, you end up with a quantum dot surrounded by flat 2D circular electron shells. So they are mimicking the atomic structure but doing away with the messy nuclear stuff so it's essentially just clean shells around the dot. This done, the key step is to build up the complete inner shells and then add one more electron to the next outer shell. This is a bit like painting multiple coats on a wall, you build up the thickness to smooth everything out. Complete shells always sum to zero, but the added electron in the incomplete outer shell can be used for the spin measurement for the qubit. Basically it's a variant of the standard approach that removes the problem of atomic imperfections, and then improves stability further by building complete orbital electron shells beneath the final electron. Apologies if this is either too technical or not technical enough, it's difficult to strike a balance, and as always with QC it can be a challenge to make sure you've understood everything correctly - I think I have, but please let me know if I've made some false connections here. Anyway, it's an interesting approach and could end up being quite an important marker on the road towards stable large-scale QC production. |
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Generally if you are not one of the 1st responses in the thread then it has already been covered, repetition is fucking boring
Of course this doesn't apply to the Flat Earth thread. That's (currently) 829 pages and 16,565 posts of solid evidence, reasoned discussion and insightful analysis, with no repetition whatsoever... |
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Different people are willing to pay different amounts for different things, depending on a variety of factors. Generally if you lack knowledge in a certain area, it can be difficult to determine what you should pay for a certain job. But in this instance, $500 is absolutely nothing to a law firm, I'd imagine it would be far cheaper for them to pay someone that sum of money than to take time out to learn how to do it for themselves.
Is it a rip-off? If it's exploiting the customer's lack of knowledge, then maybe. But if the customer vaguely understands that its a fairly simple task, but one beyond their own skillset, and they don't mind paying a small(ish) fee for someone to do it for them, then I would say no, it's reasonable.
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It's not racist.
You aren't leaving the carriage because they are Chinese, you are leaving it because of the potential of coronavirus.
If a bunch of 'normal' Chinese people got into the carriage, you wouldn't have left.
If a bunch of people of any race, wearing face masks and coughing had got into the carriage you would have left.
If a bunch of people of any race, not wearing face masks or coughing, but carrying baggage with 'Wuhan International Airport' stickers plastered over, you'd possibly have run out screaming.
The only possible route to racism here is the association you're making between Chinese people and coronavirus. Is this a legitimate link to make? Well, it's being shoved in our faces every time we look at a news report in a paper, on TV or on the web. You can't help but make the association, even if it's purely on a subconscious level.
People might be tempted to say it's the same as seeing every muslim as a terrorist, but I would argue that the muslim thing is different, and is racism. This is because in this instance you are ascribing deliberate ill-intent to every muslim you see, you are thinking every muslim is evil and wants to kill you. In the China/coronavirus case however, you are seeing the face masks and the coughing and just making the association that they may be carrying the virus. Not the same thing.
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No, XRP is not the cause of the bullish movement we've seen over the last couple of months. If it were, then we'd have seen XRP rising a) sooner than other coins, and b) more than other coins. Neither of these is the case.
The mostly likely cause I would say is the expectation of bitcoin halving, which as we all know is coming soon. Coupled to this the high bitcoin dominance at the moment, which has maybe reached the point where alts are looking like a bargain.
If any alt is helping to drive us upwards at the moment, it is ETH.
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Whilst I certainly believe that China are experimenting with bio-agents in secret labs, there are some things that make me lean towards the "natural" explanation of unsanitary conditions and illegal under-the-counter infected animals. One point in particular is the whistleblower Li Wenliang who was famously (or indeed infamously) strong-armed into silence for trying to spread the original warning. This was at the end of December. But it wasn't until 23 Jan, three and a half weeks later that China began the shutdown of Wuhan/Hubei. If it really was a government-engineered super virus, they'd not be waiting nearly a month after the initial warnings. Instead, it's likely the whistleblower would have been immediately and unequivocally silenced, in the proper Chinese style where you don't see them again for months/years afterwards if indeed ever again, and the lockdown would have been a damned sight quicker. The thing with a central economy like China is that they can do big things quickly. They could have made the shutdown instant if they'd wanted to. As for it being a deliberate leak in order to control the population, suppress unrest, etc, most of the stuff below, I don't buy that at all - China does this anyway; they've never needed an excuse before. This outbreak checks a lot of boxes the CCP likes:
-Justifies total lock down
-Effectively ends all legal dissent
-Perfect cover for rounding up dissidents
-Depopulation of an increasingly rebellious population they are losing control of & dependents
-Provides a good scapegoat for the failing economy
-Provides good fodder for spreading stories it was a Western attack to incite hatred & nationalism
-Provides a "controlled" environment to practice their bio-warfare defensive and offensive abilities
I am sure there is more, but this is what immediately comes to mind. The CCP sees life as being cheap, I wouldn't put this past them. When suspicious events happen, the first question should always be... cui bono?
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Yes, I have a few that are outside top 50 and even top 100. I won't name them because I don't want to be accused of shilling, but I am holding them long-term.
The question of whether a low cap coin is growing organically or just being pumped can be difficult to determine purely from price. Some of my low cap coins have had double digit growth in the last couple of days, but how much of this is general market movement and how much is due to the coin itself, I really don't know. That's why I tend to look longer-term on these small coins. Short-term can be difficult to read for amateurs like me.
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I think that the US is also to be blamed for those fears. They increase the tensions in the middle east by being involved there. The recent death of Suleimani for example sparkled a new fire in the region.
I agree completely. US adventurism has been the cause of much global conflict since the second world war. Kinda funny how "defence" always seems to involve invading other countries. And before the US rose to global pre-eminence, it was other Western powers. As I've said elsewhere, much of the chaos in the middle east today can be traced back to the Sykes-Picot Agreement of 1916, and the UK and France deciding how best to split the region between them. When asked about potential placement of borders by the UK Prime Minister, Sykes merely looked at the map and said "I should like to draw a line from the ‘e’ in Acre to the last ‘k’ in Kirkuk" - completely disregarding historic borders, and ancient tribes and nations and alliances. This explains why, for example, the Kurdish people nowadays are split, some in south east Turkey, some in north west Iran, some in Syria, some in Iraq... The west has a lot to answer for. |
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From a bat sandwich yes
Frankly, if I was eating a bat sandwich I'd be more surprised if I didn't contract some hideous disease. |
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The thread was started back in Jan 2018, when ETH was at it's ATH of over $1000 USD. The "ETH 2k in 2 months' time" needs to be taken in that context. Of course it seems absurd now, in retrospect, but it's easy being wise after the event. I don't think many of us expected ETH would be hit so hard for so long in that mega bear market.
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