Hash Watch: Bitcoin Cash Services Reveal Contingency Plans ...

Bob The Magic Custodian



Summary: Everyone knows that when you give your assets to someone else, they always keep them safe. If this is true for individuals, it is certainly true for businesses.
Custodians always tell the truth and manage funds properly. They won't have any interest in taking the assets as an exchange operator would. Auditors tell the truth and can't be misled. That's because organizations that are regulated are incapable of lying and don't make mistakes.

First, some background. Here is a summary of how custodians make us more secure:

Previously, we might give Alice our crypto assets to hold. There were risks:

But "no worries", Alice has a custodian named Bob. Bob is dressed in a nice suit. He knows some politicians. And he drives a Porsche. "So you have nothing to worry about!". And look at all the benefits we get:
See - all problems are solved! All we have to worry about now is:
It's pretty simple. Before we had to trust Alice. Now we only have to trust Alice, Bob, and all the ways in which they communicate. Just think of how much more secure we are!

"On top of that", Bob assures us, "we're using a special wallet structure". Bob shows Alice a diagram. "We've broken the balance up and store it in lots of smaller wallets. That way", he assures her, "a thief can't take it all at once". And he points to a historic case where a large sum was taken "because it was stored in a single wallet... how stupid".
"Very early on, we used to have all the crypto in one wallet", he said, "and then one Christmas a hacker came and took it all. We call him the Grinch. Now we individually wrap each crypto and stick it under a binary search tree. The Grinch has never been back since."

"As well", Bob continues, "even if someone were to get in, we've got insurance. It covers all thefts and even coercion, collusion, and misplaced keys - only subject to the policy terms and conditions." And with that, he pulls out a phone-book sized contract and slams it on the desk with a thud. "Yep", he continues, "we're paying top dollar for one of the best policies in the country!"
"Can I read it?' Alice asks. "Sure," Bob says, "just as soon as our legal team is done with it. They're almost through the first chapter." He pauses, then continues. "And can you believe that sales guy Mike? He has the same year Porsche as me. I mean, what are the odds?"

"Do you use multi-sig?", Alice asks. "Absolutely!" Bob replies. "All our engineers are fully trained in multi-sig. Whenever we want to set up a new wallet, we generate 2 separate keys in an air-gapped process and store them in this proprietary system here. Look, it even requires the biometric signature from one of our team members to initiate any withdrawal." He demonstrates by pressing his thumb into the display. "We use a third-party cloud validation API to match the thumbprint and authorize each withdrawal. The keys are also backed up daily to an off-site third-party."
"Wow that's really impressive," Alice says, "but what if we need access for a withdrawal outside of office hours?" "Well that's no issue", Bob says, "just send us an email, call, or text message and we always have someone on staff to help out. Just another part of our strong commitment to all our customers!"

"What about Proof of Reserve?", Alice asks. "Of course", Bob replies, "though rather than publish any blockchain addresses or signed transaction, for privacy we just do a SHA256 refactoring of the inverse hash modulus for each UTXO nonce and combine the smart contract coefficient consensus in our hyperledger lightning node. But it's really simple to use." He pushes a button and a large green checkmark appears on a screen. "See - the algorithm ran through and reserves are proven."
"Wow", Alice says, "you really know your stuff! And that is easy to use! What about fiat balances?" "Yeah, we have an auditor too", Bob replies, "Been using him for a long time so we have quite a strong relationship going! We have special books we give him every year and he's very efficient! Checks the fiat, crypto, and everything all at once!"

"We used to have a nice offline multi-sig setup we've been using without issue for the past 5 years, but I think we'll move all our funds over to your facility," Alice says. "Awesome", Bob replies, "Thanks so much! This is perfect timing too - my Porsche got a dent on it this morning. We have the paperwork right over here." "Great!", Alice replies.
And with that, Alice gets out her pen and Bob gets the contract. "Don't worry", he says, "you can take your crypto-assets back anytime you like - just subject to our cancellation policy. Our annual management fees are also super low and we don't adjust them often".

How many holes have to exist for your funds to get stolen?
Just one.

Why are we taking a powerful offline multi-sig setup, widely used globally in hundreds of different/lacking regulatory environments with 0 breaches to date, and circumventing it by a demonstrably weak third party layer? And paying a great expense to do so?
If you go through the list of breaches in the past 2 years to highly credible organizations, you go through the list of major corporate frauds (only the ones we know about), you go through the list of all the times platforms have lost funds, you go through the list of times and ways that people have lost their crypto from identity theft, hot wallet exploits, extortion, etc... and then you go through this custodian with a fine-tooth comb and truly believe they have value to add far beyond what you could, sticking your funds in a wallet (or set of wallets) they control exclusively is the absolute worst possible way to take advantage of that security.

The best way to add security for crypto-assets is to make a stronger multi-sig. With one custodian, what you are doing is giving them your cryptocurrency and hoping they're honest, competent, and flawlessly secure. It's no different than storing it on a really secure exchange. Maybe the insurance will cover you. Didn't work for Bitpay in 2015. Didn't work for Yapizon in 2017. Insurance has never paid a claim in the entire history of cryptocurrency. But maybe you'll get lucky. Maybe your exact scenario will buck the trend and be what they're willing to cover. After the large deductible and hopefully without a long and expensive court battle.

And you want to advertise this increase in risk, the lapse of judgement, an accident waiting to happen, as though it's some kind of benefit to customers ("Free institutional-grade storage for your digital assets.")? And then some people are writing to the OSC that custodians should be mandatory for all funds on every exchange platform? That this somehow will make Canadians as a whole more secure or better protected compared with standard air-gapped multi-sig? On what planet?

Most of the problems in Canada stemmed from one thing - a lack of transparency. If Canadians had known what a joke Quadriga was - it wouldn't have grown to lose $400m from hard-working Canadians from coast to coast to coast. And Gerald Cotten would be in jail, not wherever he is now (at best, rotting peacefully). EZ-BTC and mister Dave Smilie would have been a tiny little scam to his friends, not a multi-million dollar fraud. Einstein would have got their act together or been shut down BEFORE losing millions and millions more in people's funds generously donated to criminals. MapleChange wouldn't have even been a thing. And maybe we'd know a little more about CoinTradeNewNote - like how much was lost in there. Almost all of the major losses with cryptocurrency exchanges involve deception with unbacked funds.
So it's great to see transparency reports from BitBuy and ShakePay where someone independently verified the backing. The only thing we don't have is:
It's not complicated to validate cryptocurrency assets. They need to exist, they need to be spendable, and they need to cover the total balances. There are plenty of credible people and firms across the country that have the capacity to reasonably perform this validation. Having more frequent checks by different, independent, parties who publish transparent reports is far more valuable than an annual check by a single "more credible/official" party who does the exact same basic checks and may or may not publish anything. Here's an example set of requirements that could be mandated:
There are ways to structure audits such that neither crypto assets nor customer information are ever put at risk, and both can still be properly validated and publicly verifiable. There are also ways to structure audits such that they are completely reasonable for small platforms and don't inhibit innovation in any way. By making the process as reasonable as possible, we can completely eliminate any reason/excuse that an honest platform would have for not being audited. That is arguable far more important than any incremental improvement we might get from mandating "the best of the best" accountants. Right now we have nothing mandated and tons of Canadians using offshore exchanges with no oversight whatsoever.

Transparency does not prove crypto assets are safe. CoinTradeNewNote, Flexcoin ($600k), and Canadian Bitcoins ($100k) are examples where crypto-assets were breached from platforms in Canada. All of them were online wallets and used no multi-sig as far as any records show. This is consistent with what we see globally - air-gapped multi-sig wallets have an impeccable record, while other schemes tend to suffer breach after breach. We don't actually know how much CoinTrader lost because there was no visibility. Rather than publishing details of what happened, the co-founder of CoinTrader silently moved on to found another platform - the "most trusted way to buy and sell crypto" - a site that has no information whatsoever (that I could find) on the storage practices and a FAQ advising that “[t]rading cryptocurrency is completely safe” and that having your own wallet is “entirely up to you! You can certainly keep cryptocurrency, or fiat, or both, on the app.” Doesn't sound like much was learned here, which is really sad to see.
It's not that complicated or unreasonable to set up a proper hardware wallet. Multi-sig can be learned in a single course. Something the equivalent complexity of a driver's license test could prevent all the cold storage exploits we've seen to date - even globally. Platform operators have a key advantage in detecting and preventing fraud - they know their customers far better than any custodian ever would. The best job that custodians can do is to find high integrity individuals and train them to form even better wallet signatories. Rather than mandating that all platforms expose themselves to arbitrary third party risks, regulations should center around ensuring that all signatories are background-checked, properly trained, and using proper procedures. We also need to make sure that signatories are empowered with rights and responsibilities to reject and report fraud. They need to know that they can safely challenge and delay a transaction - even if it turns out they made a mistake. We need to have an environment where mistakes are brought to the surface and dealt with. Not one where firms and people feel the need to hide what happened. In addition to a knowledge-based test, an auditor can privately interview each signatory to make sure they're not in coercive situations, and we should make sure they can freely and anonymously report any issues without threat of retaliation.
A proper multi-sig has each signature held by a separate person and is governed by policies and mutual decisions instead of a hierarchy. It includes at least one redundant signature. For best results, 3of4, 3of5, 3of6, 4of5, 4of6, 4of7, 5of6, or 5of7.

History has demonstrated over and over again the risk of hot wallets even to highly credible organizations. Nonetheless, many platforms have hot wallets for convenience. While such losses are generally compensated by platforms without issue (for example Poloniex, Bitstamp, Bitfinex, Gatecoin, Coincheck, Bithumb, Zaif, CoinBene, Binance, Bitrue, Bitpoint, Upbit, VinDAX, and now KuCoin), the public tends to focus more on cases that didn't end well. Regardless of what systems are employed, there is always some level of risk. For that reason, most members of the public would prefer to see third party insurance.
Rather than trying to convince third party profit-seekers to provide comprehensive insurance and then relying on an expensive and slow legal system to enforce against whatever legal loopholes they manage to find each and every time something goes wrong, insurance could be run through multiple exchange operators and regulators, with the shared interest of having a reputable industry, keeping costs down, and taking care of Canadians. For example, a 4 of 7 multi-sig insurance fund held between 5 independent exchange operators and 2 regulatory bodies. All Canadian exchanges could pay premiums at a set rate based on their needed coverage, with a higher price paid for hot wallet coverage (anything not an air-gapped multi-sig cold wallet). Such a model would be much cheaper to manage, offer better coverage, and be much more reliable to payout when needed. The kind of coverage you could have under this model is unheard of. You could even create something like the CDIC to protect Canadians who get their trading accounts hacked if they can sufficiently prove the loss is legitimate. In cases of fraud, gross negligence, or insolvency, the fund can be used to pay affected users directly (utilizing the last transparent balance report in the worst case), something which private insurance would never touch. While it's recommended to have official policies for coverage, a model where members vote would fully cover edge cases. (Could be similar to the Supreme Court where justices vote based on case law.)
Such a model could fully protect all Canadians across all platforms. You can have a fiat coverage governed by legal agreements, and crypto-asset coverage governed by both multi-sig and legal agreements. It could be practical, affordable, and inclusive.

Now, we are at a crossroads. We can happily give up our freedom, our innovation, and our money. We can pay hefty expenses to auditors, lawyers, and regulators year after year (and make no mistake - this cost will grow to many millions or even billions as the industry grows - and it will be borne by all Canadians on every platform because platforms are not going to eat up these costs at a loss). We can make it nearly impossible for any new platform to enter the marketplace, forcing Canadians to use the same stagnant platforms year after year. We can centralize and consolidate the entire industry into 2 or 3 big players and have everyone else fail (possibly to heavy losses of users of those platforms). And when a flawed security model doesn't work and gets breached, we can make it even more complicated with even more people in suits making big money doing the job that blockchain was supposed to do in the first place. We can build a system which is so intertwined and dependent on big government, traditional finance, and central bankers that it's future depends entirely on that of the fiat system, of fractional banking, and of government bail-outs. If we choose this path, as history has shown us over and over again, we can not go back, save for revolution. Our children and grandchildren will still be paying the consequences of what we decided today.
Or, we can find solutions that work. We can maintain an open and innovative environment while making the adjustments we need to make to fully protect Canadian investors and cryptocurrency users, giving easy and affordable access to cryptocurrency for all Canadians on the platform of their choice, and creating an environment in which entrepreneurs and problem solvers can bring those solutions forward easily. None of the above precludes innovation in any way, or adds any unreasonable cost - and these three policies would demonstrably eliminate or resolve all 109 historic cases as studied here - that's every single case researched so far going back to 2011. It includes every loss that was studied so far not just in Canada but globally as well.
Unfortunately, finding answers is the least challenging part. Far more challenging is to get platform operators and regulators to agree on anything. My last post got no response whatsoever, and while the OSC has told me they're happy for industry feedback, I believe my opinion alone is fairly meaningless. This takes the whole community working together to solve. So please let me know your thoughts. Please take the time to upvote and share this with people. Please - let's get this solved and not leave it up to other people to do.

Facts/background/sources (skip if you like):



Thoughts?
submitted by azoundria2 to QuadrigaInitiative [link] [comments]

Technical: A Brief History of Payment Channels: from Satoshi to Lightning Network

Who cares about political tweets from some random country's president when payment channels are a much more interesting and are actually capable of carrying value?
So let's have a short history of various payment channel techs!

Generation 0: Satoshi's Broken nSequence Channels

Because Satoshi's Vision included payment channels, except his implementation sucked so hard we had to go fix it and added RBF as a by-product.
Originally, the plan for nSequence was that mempools would replace any transaction spending certain inputs with another transaction spending the same inputs, but only if the nSequence field of the replacement was larger.
Since 0xFFFFFFFF was the highest value that nSequence could get, this would mark a transaction as "final" and not replaceable on the mempool anymore.
In fact, this "nSequence channel" I will describe is the reason why we have this weird rule about nLockTime and nSequence. nLockTime actually only works if nSequence is not 0xFFFFFFFF i.e. final. If nSequence is 0xFFFFFFFF then nLockTime is ignored, because this if the "final" version of the transaction.
So what you'd do would be something like this:
  1. You go to a bar and promise the bartender to pay by the time the bar closes. Because this is the Bitcoin universe, time is measured in blockheight, so the closing time of the bar is indicated as some future blockheight.
  2. For your first drink, you'd make a transaction paying to the bartender for that drink, paying from some coins you have. The transaction has an nLockTime equal to the closing time of the bar, and a starting nSequence of 0. You hand over the transaction and the bartender hands you your drink.
  3. For your succeeding drink, you'd remake the same transaction, adding the payment for that drink to the transaction output that goes to the bartender (so that output keeps getting larger, by the amount of payment), and having an nSequence that is one higher than the previous one.
  4. Eventually you have to stop drinking. It comes down to one of two possibilities:
    • You drink until the bar closes. Since it is now the nLockTime indicated in the transaction, the bartender is able to broadcast the latest transaction and tells the bouncers to kick you out of the bar.
    • You wisely consider the state of your liver. So you re-sign the last transaction with a "final" nSequence of 0xFFFFFFFF i.e. the maximum possible value it can have. This allows the bartender to get his or her funds immediately (nLockTime is ignored if nSequence is 0xFFFFFFFF), so he or she tells the bouncers to let you out of the bar.
Now that of course is a payment channel. Individual payments (purchases of alcohol, so I guess buying coffee is not in scope for payment channels). Closing is done by creating a "final" transaction that is the sum of the individual payments. Sure there's no routing and channels are unidirectional and channels have a maximum lifetime but give Satoshi a break, he was also busy inventing Bitcoin at the time.
Now if you noticed I called this kind of payment channel "broken". This is because the mempool rules are not consensus rules, and cannot be validated (nothing about the mempool can be validated onchain: I sigh every time somebody proposes "let's make block size dependent on mempool size", mempool state cannot be validated by onchain data). Fullnodes can't see all of the transactions you signed, and then validate that the final one with the maximum nSequence is the one that actually is used onchain. So you can do the below:
  1. Become friends with Jihan Wu, because he owns >51% of the mining hashrate (he totally reorged Bitcoin to reverse the Binance hack right?).
  2. Slip Jihan Wu some of the more interesting drinks you're ordering as an incentive to cooperate with you. So say you end up ordering 100 drinks, you split it with Jihan Wu and give him 50 of the drinks.
  3. When the bar closes, Jihan Wu quickly calls his mining rig and tells them to mine the version of your transaction with nSequence 0. You know, that first one where you pay for only one drink.
  4. Because fullnodes cannot validate nSequence, they'll accept even the nSequence=0 version and confirm it, immutably adding you paying for a single alcoholic drink to the blockchain.
  5. The bartender, pissed at being cheated, takes out a shotgun from under the bar and shoots at you and Jihan Wu.
  6. Jihan Wu uses his mystical chi powers (actually the combined exhaust from all of his mining rigs) to slow down the shotgun pellets, making them hit you as softly as petals drifting in the wind.
  7. The bartender mutters some words, clothes ripping apart as he or she (hard to believe it could be a she but hey) turns into a bear, ready to maul you for cheating him or her of the payment for all the 100 drinks you ordered from him or her.
  8. Steely-eyed, you stand in front of the bartender-turned-bear, daring him to touch you. You've watched Revenant, you know Leonardo di Caprio could survive a bear mauling, and if some posh actor can survive that, you know you can too. You make a pose. "Drunken troll logic attack!"
  9. I think I got sidetracked here.
Lessons learned?

Spilman Channels

Incentive-compatible time-limited unidirectional channel; or, Satoshi's Vision, Fixed (if transaction malleability hadn't been a problem, that is).
Now, we know the bartender will turn into a bear and maul you if you try to cheat the payment channel, and now that we've revealed you're good friends with Jihan Wu, the bartender will no longer accept a payment channel scheme that lets one you cooperate with a miner to cheat the bartender.
Fortunately, Jeremy Spilman proposed a better way that would not let you cheat the bartender.
First, you and the bartender perform this ritual:
  1. You get some funds and create a transaction that pays to a 2-of-2 multisig between you and the bartender. You don't broadcast this yet: you just sign it and get its txid.
  2. You create another transaction that spends the above transaction. This transaction (the "backoff") has an nLockTime equal to the closing time of the bar, plus one block. You sign it and give this backoff transaction (but not the above transaction) to the bartender.
  3. The bartender signs the backoff and gives it back to you. It is now valid since it's spending a 2-of-2 of you and the bartender, and both of you have signed the backoff transaction.
  4. Now you broadcast the first transaction onchain. You and the bartender wait for it to be deeply confirmed, then you can start ordering.
The above is probably vaguely familiar to LN users. It's the funding process of payment channels! The first transaction, the one that pays to a 2-of-2 multisig, is the funding transaction that backs the payment channel funds.
So now you start ordering in this way:
  1. For your first drink, you create a transaction spending the funding transaction output and sending the price of the drink to the bartender, with the rest returning to you.
  2. You sign the transaction and pass it to the bartender, who serves your first drink.
  3. For your succeeding drinks, you recreate the same transaction, adding the price of the new drink to the sum that goes to the bartender and reducing the money returned to you. You sign the transaction and give it to the bartender, who serves you your next drink.
  4. At the end:
    • If the bar closing time is reached, the bartender signs the latest transaction, completing the needed 2-of-2 signatures and broadcasting this to the Bitcoin network. Since the backoff transaction is the closing time + 1, it can't get used at closing time.
    • If you decide you want to leave early because your liver is crying, you just tell the bartender to go ahead and close the channel (which the bartender can do at any time by just signing and broadcasting the latest transaction: the bartender won't do that because he or she is hoping you'll stay and drink more).
    • If you ended up just hanging around the bar and never ordering, then at closing time + 1 you broadcast the backoff transaction and get your funds back in full.
Now, even if you pass 50 drinks to Jihan Wu, you can't give him the first transaction (the one which pays for only one drink) and ask him to mine it: it's spending a 2-of-2 and the copy you have only contains your own signature. You need the bartender's signature to make it valid, but he or she sure as hell isn't going to cooperate in something that would lose him or her money, so a signature from the bartender validating old state where he or she gets paid less isn't going to happen.
So, problem solved, right? Right? Okay, let's try it. So you get your funds, put them in a funding tx, get the backoff tx, confirm the funding tx...
Once the funding transaction confirms deeply, the bartender laughs uproariously. He or she summons the bouncers, who surround you menacingly.
"I'm refusing service to you," the bartender says.
"Fine," you say. "I was leaving anyway;" You smirk. "I'll get back my money with the backoff transaction, and posting about your poor service on reddit so you get negative karma, so there!"
"Not so fast," the bartender says. His or her voice chills your bones. It looks like your exploitation of the Satoshi nSequence payment channel is still fresh in his or her mind. "Look at the txid of the funding transaction that got confirmed."
"What about it?" you ask nonchalantly, as you flip open your desktop computer and open a reputable blockchain explorer.
What you see shocks you.
"What the --- the txid is different! You--- you changed my signature?? But how? I put the only copy of my private key in a sealed envelope in a cast-iron box inside a safe buried in the Gobi desert protected by a clan of nomads who have dedicated their lives and their childrens' lives to keeping my private key safe in perpetuity!"
"Didn't you know?" the bartender asks. "The components of the signature are just very large numbers. The sign of one of the signature components can be changed, from positive to negative, or negative to positive, and the signature will remain valid. Anyone can do that, even if they don't know the private key. But because Bitcoin includes the signatures in the transaction when it's generating the txid, this little change also changes the txid." He or she chuckles. "They say they'll fix it by separating the signatures from the transaction body. They're saying that these kinds of signature malleability won't affect transaction ids anymore after they do this, but I bet I can get my good friend Jihan Wu to delay this 'SepSig' plan for a good while yet. Friendly guy, this Jihan Wu, it turns out all I had to do was slip him 51 drinks and he was willing to mine a tx with the signature signs flipped." His or her grin widens. "I'm afraid your backoff transaction won't work anymore, since it spends a txid that is not existent and will never be confirmed. So here's the deal. You pay me 99% of the funds in the funding transaction, in exchange for me signing the transaction that spends with the txid that you see onchain. Refuse, and you lose 100% of the funds and every other HODLer, including me, benefits from the reduction in coin supply. Accept, and you get to keep 1%. I lose nothing if you refuse, so I won't care if you do, but consider the difference of getting zilch vs. getting 1% of your funds." His or her eyes glow. "GENUFLECT RIGHT NOW."
Lesson learned?

CLTV-protected Spilman Channels

Using CLTV for the backoff branch.
This variation is simply Spilman channels, but with the backoff transaction replaced with a backoff branch in the SCRIPT you pay to. It only became possible after OP_CHECKLOCKTIMEVERIFY (CLTV) was enabled in 2015.
Now as we saw in the Spilman Channels discussion, transaction malleability means that any pre-signed offchain transaction can easily be invalidated by flipping the sign of the signature of the funding transaction while the funding transaction is not yet confirmed.
This can be avoided by simply putting any special requirements into an explicit branch of the Bitcoin SCRIPT. Now, the backoff branch is supposed to create a maximum lifetime for the payment channel, and prior to the introduction of OP_CHECKLOCKTIMEVERIFY this could only be done by having a pre-signed nLockTime transaction.
With CLTV, however, we can now make the branches explicit in the SCRIPT that the funding transaction pays to.
Instead of paying to a 2-of-2 in order to set up the funding transaction, you pay to a SCRIPT which is basically "2-of-2, OR this singlesig after a specified lock time".
With this, there is no backoff transaction that is pre-signed and which refers to a specific txid. Instead, you can create the backoff transaction later, using whatever txid the funding transaction ends up being confirmed under. Since the funding transaction is immutable once confirmed, it is no longer possible to change the txid afterwards.

Todd Micropayment Networks

The old hub-spoke model (that isn't how LN today actually works).
One of the more direct predecessors of the Lightning Network was the hub-spoke model discussed by Peter Todd. In this model, instead of payers directly having channels to payees, payers and payees connect to a central hub server. This allows any payer to pay any payee, using the same channel for every payee on the hub. Similarly, this allows any payee to receive from any payer, using the same channel.
Remember from the above Spilman example? When you open a channel to the bartender, you have to wait around for the funding tx to confirm. This will take an hour at best. Now consider that you have to make channels for everyone you want to pay to. That's not very scalable.
So the Todd hub-spoke model has a central "clearing house" that transport money from payers to payees. The "Moonbeam" project takes this model. Of course, this reveals to the hub who the payer and payee are, and thus the hub can potentially censor transactions. Generally, though, it was considered that a hub would more efficiently censor by just not maintaining a channel with the payer or payee that it wants to censor (since the money it owned in the channel would just be locked uselessly if the hub won't process payments to/from the censored user).
In any case, the ability of the central hub to monitor payments means that it can surveill the payer and payee, and then sell this private transactional data to third parties. This loss of privacy would be intolerable today.
Peter Todd also proposed that there might be multiple hubs that could transport funds to each other on behalf of their users, providing somewhat better privacy.
Another point of note is that at the time such networks were proposed, only unidirectional (Spilman) channels were available. Thus, while one could be a payer, or payee, you would have to use separate channels for your income versus for your spending. Worse, if you wanted to transfer money from your income channel to your spending channel, you had to close both and reshuffle the money between them, both onchain activities.

Poon-Dryja Lightning Network

Bidirectional two-participant channels.
The Poon-Dryja channel mechanism has two important properties:
Both the original Satoshi and the two Spilman variants are unidirectional: there is a payer and a payee, and if the payee wants to do a refund, or wants to pay for a different service or product the payer is providing, then they can't use the same unidirectional channel.
The Poon-Dryjam mechanism allows channels, however, to be bidirectional instead: you are not a payer or a payee on the channel, you can receive or send at any time as long as both you and the channel counterparty are online.
Further, unlike either of the Spilman variants, there is no time limit for the lifetime of a channel. Instead, you can keep the channel open for as long as you want.
Both properties, together, form a very powerful scaling property that I believe most people have not appreciated. With unidirectional channels, as mentioned before, if you both earn and spend over the same network of payment channels, you would have separate channels for earning and spending. You would then need to perform onchain operations to "reverse" the directions of your channels periodically. Secondly, since Spilman channels have a fixed lifetime, even if you never used either channel, you would have to periodically "refresh" it by closing it and reopening.
With bidirectional, indefinite-lifetime channels, you may instead open some channels when you first begin managing your own money, then close them only after your lawyers have executed your last will and testament on how the money in your channels get divided up to your heirs: that's just two onchain transactions in your entire lifetime. That is the potentially very powerful scaling property that bidirectional, indefinite-lifetime channels allow.
I won't discuss the transaction structure needed for Poon-Dryja bidirectional channels --- it's complicated and you can easily get explanations with cute graphics elsewhere.
There is a weakness of Poon-Dryja that people tend to gloss over (because it was fixed very well by RustyReddit):
Another thing I want to emphasize is that while the Lightning Network paper and many of the earlier presentations developed from the old Peter Todd hub-and-spoke model, the modern Lightning Network takes the logical conclusion of removing a strict separation between "hubs" and "spokes". Any node on the Lightning Network can very well work as a hub for any other node. Thus, while you might operate as "mostly a payer", "mostly a forwarding node", "mostly a payee", you still end up being at least partially a forwarding node ("hub") on the network, at least part of the time. This greatly reduces the problems of privacy inherent in having only a few hub nodes: forwarding nodes cannot get significantly useful data from the payments passing through them, because the distance between the payer and the payee can be so large that it would be likely that the ultimate payer and the ultimate payee could be anyone on the Lightning Network.
Lessons learned?

Future

After LN, there's also the Decker-Wattenhofer Duplex Micropayment Channels (DMC). This post is long enough as-is, LOL. But for now, it uses a novel "decrementing nSequence channel", using the new relative-timelock semantics of nSequence (not the broken one originally by Satoshi). It actually uses multiple such "decrementing nSequence" constructs, terminating in a pair of Spilman channels, one in both directions (thus "duplex"). Maybe I'll discuss it some other time.
The realization that channel constructions could actually hold more channel constructions inside them (the way the Decker-Wattenhofer puts a pair of Spilman channels inside a series of "decrementing nSequence channels") lead to the further thought behind Burchert-Decker-Wattenhofer channel factories. Basically, you could host multiple two-participant channel constructs inside a larger multiparticipant "channel" construct (i.e. host multiple channels inside a factory).
Further, we have the Decker-Russell-Osuntokun or "eltoo" construction. I'd argue that this is "nSequence done right". I'll write more about this later, because this post is long enough.
Lessons learned?
submitted by almkglor to Bitcoin [link] [comments]

Goodbye, Coinbase. Hello APPC: An alternative method to purchase cryptocurrency directly from the Android "Aptoide" app store. 200 million Android users will be holding cryptocurrency by the end of this year.

I recently stumbled upon the "APPC", or "AppCoins" token on Binance while browsing new coin listings.
Like any half-decent cryptocurrency enthusiast, I was intrigued. "Aha! A new coin!"
I took a deep breath and prepared to take a deep dive into the bowels of the internet to figure out what APPC is all about. And by deep dive I mean I googled "AppCoins" and went to their website.
"Oh, they're trying to make a new app store. Good luck competing with Google Play and the iOS App Store!"
Given Google and Apple's combined gigantic market share of the space, I was inclined to move on to the next lucky contestant on the Wheel O' Coins. But on a whim I kept scrolling.
I thought "Wait, what? 200 million users? Over 4 billion downloads? What am I missing here?"
Apparently AppCoins isn't a token from a new startup - it's the token from Aptoide, the #1 ranked alternative to the Google Play store.
From the developer's side, the token is used as an incentive for users to download their apps. The end user is rewarded with tokens based on a unique system that determines if the user is actually trying out the app. The tokens are also used for in-app purchases. They can also be sent to and from one another.
But enough about the token value proposition. You can research it in depth yourself and buy some on Binance if you're so inclined. Whether or not you buy the coin for speculation purposes is not the purpose of this post.
So...what does this have to do with Coinbase?
Well, let's first take a quick look at the AppCoins roadmap:
By the end of this year over 200 million Aptoide users will have the ability to purchase, earn, and use AppCoins from right within the app.
To give some perspective, Coinbase has 13.3 million users as of October 26, 2017 according to an article from CNBC.
Aptoide has over 15 times the number of active users compared to Coinbase.
OK, you have my attention. Starting to sound like a shill post though. Get to the beef.
Buying cryptocurrency through Coinbase is expensive. Users are nickle-and-dimed at every opportunity:
Let's say you're not interested in buying Bitcoin, Bitcoin Cash, Ethereum, or Litecoin.
Instead you want to convert your hard-earned $2,000 US dollars into something else like Ripple. Here's how it plays out:
Your initial deposit: $2,000 Deposit fee: $0 (ACH to receive funds in 3-5 days) through $79.80 for debit/credit card fees
Now you have $1,920.20 - $2,000 in your Coinbase USD wallet
You decide to purchase ETH with the intention of transferring it to an exchange that sells Ripple:
ETH buy order: $1,920.20 - $2,000 Transaction fee: $29.80 for ACH. Fee included in credit/debit deposit (so $79.80).
Total purchase fees from deposit to ETH acquisition: $29.80 to 79.80
EDIT: Adjusted the fee rate schedule to make them accurate. Do these fees still seem reasonable to you, even after the decrease in fees? Search Reddit for complaints about Coinbase fees and see what you find. And if you're unconcerned about the deposit transaction price, how about the speed of transaction to fee rate ratio? If we want cryptocurrency to be widely adopted then it should be friction-less.
Come on. Everyone knows that Coinbase is expensive. That's why I deposit my fiat into GDAX to buy crypto. The fees are significantly lower. Quit wasting my time.
Well, that's partially true. Anyone worth their weight in SHA256 hashes knows that GDAX is dramatically cheaper than Coinbase for depositing and purchasing BTC, BCH, LTC, and ETH.
The part that isn't true is that everyone knows that GDAX is cheaper. A more accurate statement is "every cryptocurrency enthusiast/trader knows that GDAX is cheaper". Coinbase does not advertise that GDAX has cheaper fees. There is no GDAX app for a reason - it would heavily cut into Coinbase's bottom line.
Your average crypto newbie buys their first coins through Coinbase because, let's face it, they have an app. Buying crypto on an app is something that your average person can comprehend. Apps are easy to use, trustworthy, and nearly everyone can do it regardless of their age and technical skill level.
Right, apps are easy to use. What a novel thought. You should tour the world giving Ted Talks about how easy apps are to use. Now could you PLEASE get to the point.
OK! I apologize for droning on. I'll cut right to the chase:
Instead of jumping through all the aforementioned hoops with Coinbase, you buy AppCoins from the Aptoide app store and send them directly to your favorite exchange. Then trade the AppCoins for the cryptocurrency of your choice. In theory it should be a faster and more cost-effective way to purchase cryptocurrency.
Hmmmm. OK, I'm starting to understand where you're going with this. But I'm still going to use GDAX. I'd rather buy ETH from GDAX.
Hey, to each their own. I'd rather buy coins in 30 seconds with a couple of taps on my phone and send them right to Binance.
Oh come on. Now you're just shilling. Your whole rant was just a ploy to shill this coin. I'm going to another thread.
Honestly, no. I didn't write this to shill. I guess I'm just tired of Coinbase. And I bet there are others that are less than pleased with their business model and customer service. Remember when they didn't distribute all that Bitcoin Cash?
Ugh, yes. Don't remind me about that.
Sorry! Didn't mean to upset you. I know its a sore subject.
If you read this far then congratulations, you have more patience than your average cryptocurrency trader. May your candles always be green.
Some interesting facts:
Needless to say, I think that Aptoide and AppCoins is a project to be excited about regardless of whether you're a cryptocurrency trader or completely uninvolved with the cryptocurrency space. Cryptocurrency is going mainstream this year!
To avoid confusion since Coinmarketcap has APPC listed incorrectly, here is the current accurate financial information. People are going to ask anyway so I would rather supply the correct information:
Circulating supply= 98M APPC Total supply= 246M APPC Coin Price = $2.53 ICO Price = $0.10 Market Cap (CS x P) = $247,940,000 Days on Exchange (Binance) = 7
Thank you for reading!
EDIT: Spelling
submitted by Deliverah to CryptoCurrency [link] [comments]

Please Send this to Binance

I haven't seen anything on Binance about this:

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256
Dear participants of the Monero ecosystem,
We would like to inform you that we will be phasing out long payment IDs this year. Long payment IDs are detrimental to privacy and a source of negative user experience (as well as additional support work for services). Services will have to upgrade to either integrated addresses or subaddresses. Note, however, that there is some discussion about phasing out integrated addresses as well. Therefore, services are, to avoid having to potentially perform additional work, encouraged to upgrade to subaddresses directly.
Long payment IDs will be phased out because they have several salient drawbacks. First, long payment IDs are detrimental to privacy insofar as they can potentially link the transactions of a user in case of reusage. Second, long payment IDs have to be attached separately to a transaction. This is inconsistent with conventional cryptocurrency transactions and therefore unintuitive for the user. As a result, users occasionally forget to attach the long payment ID when sending their transaction to a service and thus have to go through support to 'recover' their funds. Third, it logically follows from the previous point that long payment IDs cause additional support work for services. Fourth, only one long payment ID can be attached to a transaction. Thus, services cannot batch withdrawals of multiple users specifying a long payment ID. By contrast, subaddresses have no such restriction and withdrawals can thus all be batched.
In sum, payment IDs have serveral salient drawbacks and will therefore be phased out. Services are recommended to upgrade to subaddresses as soon as possible. Subaddresses essentially function similar to Bitcoin HD wallets and should thus be relatively straightforward to implement. Furthermore, subaddresses are managable from a resource point point of view.
Yours sincerely,
The Monero dev community
Appendix:
An upgrade process PDF that may be useful for you can be found here: https://github.com/monero-project/meta/files/2775745/Upgrade.Process.pdf -----BEGIN PGP SIGNATURE-----
iQEzBAEBCAAdFiEElLc43TUBMvWsvuodVUMt8xzNT80FAlz2zVEACgkQVUMt8xzN T81t/AgAvRjwdOUetF/N/uzc0WLCHK6iSzUo/J6li/zmJrHa2SS2JXCxcSZSae6k 6w2UXOW0qHfr5YTJCHiwR+nLWNYFFUh941Q9RRE5yQgrWKLrfKN0pxVqziHdKkkC Z2P7V+cqOAkrSFoxvBqdZNrKaoIF9sC2zoof313rUCWHoOlYjnnCjzRwfSOZ+JAb CmSahfeDLfTEObWsB7PqbOsXj1hfEnUf/71vauolZAGqDH+qyyu3/AT47q6iWQm8 yFb677/FV+kgDF+kiTAqOg5dPsAxnp8vEP8jHVXBQ4qvG1VsefsQTvfGG0B4k0fp u+F1CZqKBE1Bn6L4ybNYAXmTGbKpWg== =I7Yn -----END PGP SIGNATURE-----
submitted by imissusenet to Monero [link] [comments]

ICO Airdrop Bounty Hard fork smart contract ERC20 mining pool DApp Nhung khai niem co ban ban can biet khi tham gia vao thi truong Cryptocurrency

ICO Airdrop Bounty Hard fork smart contract ERC20 mining pool DApp Nhung khai niem co ban ban can biet khi tham gia vao thi truong Cryptocurrency
Blockchain và cryptocurrency là những lĩnh vực đầy mới mẻ, có nhiều khái niệm phức tạp với đa số công chúng. Xoay quanh tiền mã hóa, có những ý tưởng về ICO, hard fork, soft fork, ứng dụng phân quyền (DApp), hợp đồng thông minh (smart contract), Airdrop/Bounty, token ERC20, mining pool,… nổi cộm cần chúng ta nắm bắt. Vậy hôm nay, tiendientu.org xin giải thích đến các bạn những khái niệm cơ bản nhất cần nắm vững trước khi bước chân vào lĩnh vực cryptocurrency.

1. ICO là gì?

ICO là gì? ICO (viết tắt của từ Initial Coin Offering) là một hình thức kêu gọi vốn đầu tư khá phổ biến trong các dự án cryptocurrency. Khi một công ty hay đội ngũ muốn phát hành cryptocurrency riêng, họ thường tạo ra một số lượng token nhất định và bán những token này cho nhà đầu tư trong các đợt mở bán, kêu gọi vốn đầu tư khác nhau.

Thông thường đội ngũ nhà phát triển sẽ chấp nhận cho nhà đầu tư thanh toán bằng Bitcoin hoặc Ethereum.

ICO là gì?

Nếu trong tài chính truyền thống, phát hành chứng khoán lần đầu ra công chúng là IPO thì ICO là đặc điểm riêng của cryptocurrency. ICO đại diện cho một hình thức kêu gọi vốn đầu tư thế hế mới, dựa trên niềm tin của cộng đồng với dự án đang phát triển, cũng như với đội ngũ và tiềm năng của nó. ICO ra đời giải quyết vấn đề nổi cộm là nhiều start-up có ý tưởng hay, công nghệ đột phá nhưng chưa có đủ vốn liếng để xây dựng – họ sẽ tìm đến ICO.

Vậy nhà đầu tư được lợi gì khi đầu tư ICO? Trước hết, lưu ý là không phải ICO nào cũng toàn”màu hường”, có những dự án rởm, lừa đảo hay đầu voi đuôi chuột nhan nhản trong cộng đồng. Nhưng nếu nhà đầu tư đã chọn lọc kỹ càng, chi tiền cho những ICO thực sự có tiềm năng, thì khi sản phẩm thực ra đời, token được lên sàn và chấp nhận rộng rãi thì giá token sẽ tăng vượt bậc so với giá khi nhà đầu tư mua vào lúc ICO. Và đó chính là lợi nhuận.

2. Token là gì?

Được nhắc đến ở trên, vậy token là gì?

Token là đồng tiền mã hóa được phát hành trong các đợt ICO. Token được phát hành dựa trên một nền tảng của coin nào đó. Ví dụ đa số token hiện tại được phát hành trên nền tảng Ethereum dựa theo chuẩn ERC-20. Một số token khác dựa trên nền tảng NEO, WAVES, STELLAR và có cả Bitcoin.
Token là gì?
Có thể phân token thành 2 loại dựa theo tính năng như sau:

2.1. Ultility Token là gì?

Ultility Token là token tiện ích. Ultility token được sinh ra để phục vụ cho một dự án với mục tiêu và tính năng cụ thể. Ví dụ, BNB token của Binance có tính năng giảm giá phí giao dịch…

2.2. Security Token là gì?

Security Token hay còn gọi là token chứng khoán là một dạng cổ phiếu điện tử phát hành dưới dạng token. Bạn sẽ được hưởng cổ tức dựa trên số cổ phần bạn sở hữu của dự án đó. Security token còn cho phép bạn có quyền bầu chọn hoặc tham gia quyết định một số công việc của dự án.

2.3. Lưu trữ token ở ví nào?

Bạn cần phải xác định được token đó hoạt động trên nền tảng blockchain nào.

  • Token của Ethereum: lưu trữ tại ví Ethereum như MyEtherWallet, MetaMask, Eidoo, ImToken…
  • Token của NEO: lưu trữ tại ví NeoTracker Walllet.
  • Token của Stellar: lưu trữ tại ví Stratis Wallet.
  • Tương tự với các nền tảng khác như Waves, QTUM, NEM…

3. ERC20 là gì?

ERC-20 là một tiêu chuẩn kỹ thuật được sử dụng cho các hợp đồng thông minh trên blockchain của Ethereum khi phát hành Token.

ERC20 là gì?

Địa chỉ ví của Token sử dụng công nghệ ERC20 sẽ có gán thêm 0x ở đầu và các loại Token này đều mua bằng Ethereum. Có thể lưu trữ token ERC20 ở ví MyEtherWallet một cách dễ dàng. Toàn bộ token ERC20 đều được giao dịch trên mạng lưới của Ethereum. Do đó địa chỉ ETH cũng là địa chỉ của các token đó.

Một ưu điểm ở công nghệ ERC20 là sự kết hợp với hợp đồng thông minh. Điều này sẽ giúp bạn giao dịch an toàn hơn, trong trường hợp bạn gửi Token cho người khác nhưng sai địa chỉ ví thì công nghệ này nó sẽ báo lỗi địa chỉ ví và bạn không thể gửi Token cho người khác được. Điều này rất tuyệt với nó sẽ giúp bạn bảo vệ tài sản của mình tốt nhất có thể.

Các Token sử dụng công nghệ ERC20 ngày càng trở nên phổ biến hơn. Thống kê vào đầu năm 2018 thì hầu hết các Token ban hành ra thị trường đều sử dụng trên nền tảng ERC20. Trong tương lại công nghệ này sẽ chiếm lĩnh thị trường và sẽ là nền tảng tốt nhất để phát triển các loại Token mới.

4. Smart Contract là gì?

Trong khi một hợp đồng bình thường bao gồm các điều khoản ràng buộc mối quan hệ của hai bên đối tác thì smart contract (hợp đồng thông minh) ràng buộc mối quan hệ đó bằng mã code.

Smart Contract là gì?
Đặc biệt hơn, các hợp đồng thông minh này sẽ thực thi những điều khoản đó một cách chính xác kể từ khi nó được lập trình bởi người sáng lập.

Trong một ví dụ đơn giản khác, người sử dụng Ethereum có thể gửi 10 ETH cho bạn của mình vào một ngày nào đó bằng smart contract. Trong trường hợp này, người dùng sẽ tạo một hợp đồng và để dữ liệu vào hợp đồng đó. Sau đó, hợp đồng này sẽ tự động thực thi theo lệnh đã được lập trình ban đầu.

5. DApp là gì?

White Paper của Ethereum phân chia Dapp (ứng dụng phân quyền) thành ba loại: các ứng dụng tài chính, các ứng dụng có liên quan đến tài chính (nhưng cũng cần một phần khác) và ứng dụng hoàn toàn khác như hệ thống bầu cử và quản trị.

Trong loại ứng dụng đầu tiên, người dùng có thể cần phải trao đổi Ether như là một cách để giải quyết hợp đồng với người dùng khác, sử dụng các node máy tính phân tán của mạng để tạo điều kiện cho việc phân phối dữ liệu.

Loại thứ hai là ứng dụng kết hợp tiền với thông tin từ bên ngoài blockchain.

DApp là gì?

Ví dụ, một ứng dụng bảo hiểm mùa màng phụ thuộc vào nguồn cung cấp thông tin thời tiết bên ngoài. Nếu một người nông dân sử dụng ứng dụng này, hệ thống sẽ tự động trả phí bảo hiểm nếu có hạn hán ảnh hưởng đến công việc của ông ấy.

Để thực hiện những hợp đồng thông minh này, ứng dụng dựa vào “oracles” – một hệ quản trị dữ liệu – để cập nhật thông tin về thế giới bên ngoài. Tuy nhiên, cần lưu ý là một số nhà phát triển hoài nghi rằng trường hợp sử dụng này có thể được thực hiện theo cách phân quyền.

Các tổ chức tự vận hành phân quyền là một trong những ý tưởng mô hình quản trị đầy tham vọng nhất của Dapp – loại thứ ba. Chẳng hạn như DAO App có mục tiêu là hình thành nên một công ty không có vị trí lãnh đạo, các quy tắc được lập trình ngay từ đầu về cách các thành viên có thể bỏ phiếu và làm thế nào để phát hành quỹ của công ty và sau đó … để cho nó tự vận hành.

6. Hard fork – Soft fork là gì?

6.1. Fork là gì?

Fork là một từ kỹ thuật thường được dùng bởi các nhà phát triển trong các dự án mã nguồn mở. Nó đơn giản chỉ là “cập nhật phần mềm” hay “sửa lỗi”. Ví dụ khi bạn cập nhật một ứng dụng trên chiếc smartphone (mobile app) thì bạn đã có được một bản Fork từ phiên bản cũ. Vì thế, khái niệm Fork trong Bitcoin và cryptocurrency cũng tương tự như vậy.

Đối với tiền mã hóa sẽ có hai loại Fork khác nhau là: Hard Fork và Soft Fork.

Hard fork – Soft fork là gì?

6.2. Hard Fork là gì?

Hard Fork là một bản cập nhật phần mềm bắt buộc và sẽ gây xung đột với phiên bản cũ hơn. Chương trình bị Fork sẽ không chạy được nếu không cập nhật nó. Ví dụ, có một lỗi (bug) quan trọng trong phần mềm, nếu muốn tiếp tục sử dụng thì cần phải cập nhật phần mềm.

Nếu không cập nhật – sẽ không sử dụng được chương trình. Ngoài ra, không có cách nào để đảo ngược một Hard Fork, trừ trường hợp có một số lỗi không mong đợi hay các vấn đề đi kèm. Đó là trường hợp sẽ phải làm thêm một Hard Fork và trở lại với phiên bản cũ.

Hard fork Bitcoin nổi tiếng nhất chính là Bitcoin Cash.

6.3. Soft Fork là gì?

Soft Fork là một bản cập nhật phần mềm không gây xung đột với phiên bản cũ hơn, nó không bắt buộc và cho phép mạng điều chỉnh thêm các tính năng mới trong khi đang xử lý. Mặc dù một Soft Fork đang cài đặt ngay cả khi máy tính chạy với chương trình cũ thì vẫn có thể sử dụng.

Nếu Soft Fork không hoạt động, có lỗi hay mọi người không chấp nhận nó thì nó hoàn toàn có thể đảo ngược và có thể trở lại với phiên bản cũ. Hầu hết các phần mềm bạn sử dụng ngày nay đều được kiểm soát bởi một thực thể duy nhất. Vì vậy, bất kỳ khi nào họ muốn Fork từ chương trình gốc thì chỉ cần cập nhật dưới hình thức một Soft Fork.


Phân biệt Hard fork và Soft fork.

7. Airdrop/Bounty là gì?

7.1. Airdrop là gì?

Airdrop đơn giản có nghĩa là “từ trên trời rơi xuống”. Nhưng trong thị trường cryptocurrency thì Airdrop là một khái niệm mới, có nghĩa là tiến hành phát các token/coin miễn phí vào ví của người dùng, khi người dùng đó thực hiện công việc là đăng ký tài khoản và giới thiệu người khác đăng ký tài khoản để nhận được các token miễn phí.

Đã có rất nhiều người kiếm được hàng trăm USD từ các đợt airdrop tiền mã hóa. Airdrop thường được sử dụng cho hoạt động ICO, với mục đích là quảng bá thương hiệu cũng như khuấy động sự hứng thú đối với dự án của mọi người.

7.2. Bounty là gì?

Bounty (săn phần thưởng) là hình thức bạn phải làm theo những yêu cầu nhất định, để đổi lại số lượng coin miễn phí nhất định khi hoàn thành những yêu cầu đó. Đây là một cách mà các coin mới cũng thực hiện rất nhiều, song song với những đợt Airdrop.


Airdrop/Bounty là gì?

Một số yêu cầu thông dụng trong Bounty như:
  • Đặt chữ ký trên Bitcointalk
  • Follow kênh Telegram
  • Viết bài giới thiệu dự án trên blog, medium
  • Follow, tweet trên Twitter
  • Đăng bài trên Facebook
  • Đăng bài, follow trên Linkedin
Ngoài ra, một số coin sẽ có các yêu cầu rất cao như phải like, share 3 – 5 bài viết của họ mỗi tuần, share nhiều thì được nhiều; tham gia kênh Telegram của họ hay phải đăng những link bài bạn share vào topic Bounty của họ trên bitcointalk.org hay phải share bài kèm hashtag (ví dụ như #ICO #ETH …), hoặc yêu cầu mỗi ngày chỉ được share 1 bài.

8. Mining Pool là gì?

Một trong những câu hỏi đầu tiên mà ai hứng thú đến việc đào cryptocurrency đều đặt ra đó là – máy đào tự chơi một mình hay tham gia vào các mining pool. Có nhiều lý do bạn nên và không nên tham gia vào pool. Tuy nhiên, nếu sự phân chia tốc độ Hash trên network Bitcoin phụ thuộc vào số máy đào nhiều hay ít, thì hầu hết nhà đào đều lựa chọn tham gia mining pool.


Mining Pool là gì?

Nếu đang do dự có nên tham gia vào mining pool hay không, bạn nên xem pool như là mô hình xổ số – với những ưu điểm và nhược điểm hoàn toàn giống nhau. Hoạt động một mình thì bạn không phải chia sẻ phần thưởng, nhưng tỷ lệ bạn đạt thưởng sẽ nhỏ đi rất nhiều. Mặc dù pool có cơ hội giải được block và giành được thưởng cao hơn, nhưng phần thưởng sẽ phải chia sẻ cho những thành viên tham gia pool.

Do đó, tham gia vào pool tạo ra một nguồn thu nhập ổn định, đều đặn, dù mỗi khoản bạn nhận được nhỏ hơn rất nhiều so với phần thưởng đầy đủ.

Dĩ nhiên, Bitcoin không chỉ là đồng coin duy nhất được đào ra – rất dễ để tìm thấy danh sách những pool đào cryptocurrency mà bạn đang nhắm đến.

Với những thợ đào mới tham gia – thiếu phần cứng đủ mạnh mẽ, thì có thể đào Altcoin thay vì Bitcoin – đặc biệt là những đồng tiền dựa trên thuật toán scrypt hơn là SHA256. Lý do là vì giải thuật Bitcoin rất khó khăn khi dùng những máy tính để bàn thông thường.

9. Tóm tắt

ICO là gì? ICO là một hình thức kêu gọi vốn đầu tư phổ biến trong các dự án cryptocurrency. Tương tự IPO với thị trường chứng khoán truyền thống.

Token là gì? Token là đồng tiền mã hóa được phát hành trong các đợt ICO. Token được phát hành dựa trên một nền tảng của coin nào đó.


ICO, Airdrop, Bounty, Hard fork, smart contract, ERC20, mining pool, DApp,… Những khái niệm cơ bản bạn cần biết khi tham gia vào thị trường Cryptocurrency?

ERC20 là gì? ERC-20 là một tiêu chuẩn kỹ thuật được sử dụng cho các hợp đồng thông minh trên blockchain của Ethereum khi phát hành Token.

Smart Contract là gì? Trong khi một hợp đồng bình thường bao gồm các điều khoản ràng buộc mối quan hệ của hai bên đối tác thì smart contract (hợp đồng thông minh) ràng buộc mối quan hệ đó bằng mã code.

DApp là gì? DApp (ứng dụng phân quyền) là những ứng dụng được xây dựng trên nền tảng blockchain, phục vụ vì những mục đích khác nhau. Khác với ứng dụng (app) thông thường trên di động, DApp mang trong mình những ưu điểm của công nghệ blockchain.

Hard Fork là gì? Hard Fork là một bản cập nhật phần mềm/blockchain bắt buộc và sẽ gây xung đột với phiên bản cũ hơn.

Soft Fork là gì? Khác với Hard Fork, Soft Fork là phiên bản cập nhật mới nhưng không bắt buộc, bản cũ và mới có thể chạy song song.

Airdrop/Bounty là gì? Airdrop/Bounty là những hình thức phân phát coin miễn phí cho người dùng, thường là với những coin/token mới cần được biết đến rộng rãi trong cộng đồng.

Mining Pool là gì? Để đào coin, thợ đào có thể tự trang bị máy đào tại nhà, tự khai thác một mình, hoặc lựa chọn tham gia vào các mining pool lớn – tập trung số lượng máy đào cao để tăng tính cạnh tranh, từ đó tăng xác suất đào được coin và có lợi nhuận.

Cập nhật tin tức mới nhất về blockchain và cryptocurrency tại Tiendientu.org
submitted by tiendientuorg to u/tiendientuorg [link] [comments]

[uncensored-r/CryptoCurrency] Goodbye, Coinbase. Hello APPC: An alternative method to purchase cryptocurrency directly from the...

The following post by Deliverah is being replicated because some comments within the post(but not the post itself) have been openly removed.
The original post can be found(in censored form) at this link:
np.reddit.com/ CryptoCurrency/comments/7pvfsw
The original post's content was as follows:
I recently stumbled upon the "APPC", or "AppCoins" token on Binance while browsing new coin listings.
Like any half-decent cryptocurrency enthusiast, I was intrigued. "Aha! A new coin!"
I took a deep breath and prepared to take a deep dive into the bowels of the internet to figure out what APPC is all about. And by deep dive I mean I googled "AppCoins" and went to their website.
"Oh, they're trying to make a new app store. Good luck competing with Google Play and the iOS App Store!"
Given Google and Apple's combined gigantic market share of the space, I was inclined to move on to the next lucky contestant on the Wheel O' Coins. But on a whim I kept scrolling.
I thought "Wait, what? 200 million users? Over 4 billion downloads? What am I missing here?"
Apparently AppCoins isn't a token from a new startup - it's the token from Aptoide, the #1 ranked alternative to the Google Play store.
From the developer's side, the token is used as an incentive for users to download their apps. The end user is rewarded with tokens based on a unique system that determines if the user is actually trying out the app. The tokens are also used for in-app purchases. They can also be sent to and from one another.
But enough about the token value proposition. You can research it in depth yourself and buy some on Binance if you're so inclined. Whether or not you buy the coin for speculation purposes is not the purpose of this post.
So...what does this have to do with Coinbase?
Well, let's first take a quick look at the AppCoins roadmap:
  • Q1 - Open Source Implementation: Release of the first beta version of Aptoide with AppCoins support
  • Q2 - Pre Load Tier 1 OEMs: Rollout of AppCoins on Aptoide App Store, as well as on other app stores that joined
  • Q3 - App Store Foundation: Production roll-out to all Aptoide clients (and other participant app stores)
By the end of this year over 200 million Aptoide users will have the ability to purchase, earn, and use AppCoins from right within the app.
To give some perspective, Coinbase has 13.3 million users as of October 26, 2017 according to an article from CNBC.
Aptoide has over 15 times the number of active users compared to Coinbase.
OK, you have my attention. Starting to sound like a shill post though. Get to the beef.
Buying cryptocurrency through Coinbase is expensive. Users are nickle-and-dimed at every opportunity:
  • Deposit fees: Free (ACH to receive funds in 3-5 days) through 3.99% for debit/credit card fees
  • Transaction fees: from $0.99 to $2.99. It's a $2.99 + 1.49% variable fee for purchases over $200.
Let's say you're not interested in buying Bitcoin, Bitcoin Cash, Ethereum, or Litecoin.
Instead you want to convert your hard-earned $2,000 US dollars into something else like Ripple. Here's how it plays out:
Your initial deposit: $2,000 Deposit fee: $0 (ACH to receive funds in 3-5 days) through $79.80 for debit/credit card fees
Now you have $1,920.20 - $2,000 in your Coinbase USD wallet
You decide to purchase ETH with the intention of transferring it to an exchange that sells Ripple:
ETH buy order: $1,920.20 - $2,000 Transaction fee: $29.80 for ACH. Fee included in credit/debit deposit (so $79.80).
Total purchase fees from deposit to ETH acquisition: $29.80 to 79.80
EDIT: Adjusted the fee rate schedule to make them accurate. Do these fees still seem reasonable to you, even after the decrease in fees? Search Reddit for complaints about Coinbase fees and see what you find. And if your unconcerned about the deposit transaction price, how about the speed of transaction to fee rate ratio? If we want cryptocurrency to be widely adopted then it should be friction-less.
Come on. Everyone knows that Coinbase is expensive. That's why I deposit my fiat into GDAX to buy crypto. The fees are significantly lower. Quit wasting my time.
Well, that's partially true. Anyone worth their weight in SHA256 hashes knows that GDAX is dramatically cheaper than Coinbase for depositing and purchasing BTC, BCH, LTC, and ETH.
The part that isn't true is that everyone knows that GDAX is cheaper. A more accurate statement is "every cryptocurrency enthusiast/trader knows that GDAX is cheaper". Coinbase does not advertise that GDAX has cheaper fees. There is no GDAX app for a reason - it would heavily cut into Coinbase's bottom line.
Your average crypto newbie buys their first coins through Coinbase because, let's face it, they have an app. Buying crypto on an app is something that your average person can comprehend. Apps are easy to use, trustworthy, and nearly everyone can do it regardless of their age and technical skill level.
Right, apps are easy to use. What a novel thought. You should tour the world giving Ted Talks about how easy apps are to use. Now could you PLEASE get to the point.
OK! I apologize for droning on. I'll cut right to the chase:
Instead of jumping through all the aforementioned hoops with Coinbase, you buy AppCoins from the Aptoide app store and send them directly to your favorite exchange. Then trade the AppCoins for the cryptocurrency of your choice. In theory it should be a faster and more cost-effective way to purchase cryptocurrency.
Hmmmm. OK, I'm starting to understand where you're going with this. But I'm still going to use GDAX. I'd rather buy ETH from GDAX.
Hey, to each their own. I'd rather buy coins in 30 seconds with a couple of taps on my phone and send them right to Binance.
Oh come on. Now you're just shilling. Your whole rant was just a ploy to shill this coin. I'm going to another thread.
Honestly, no. I didn't write this to shill. I guess I'm just tired of Coinbase. And I bet there are others that are less than pleased with their business model and customer service. Remember when they didn't distribute all that Bitcoin Cash?
Ugh, yes. Don't remind me about that.
Sorry! Didn't mean to upset you. I know its a sore subject.
If you read this far then congratulations, you have more patience than your average cryptocurrency trader. May your candles always be green.
Some interesting facts:
  • The number of Bitcoin users is forecasted to reach 200 million by 2024.
  • There are approximately 15 million bitcoin wallets as of September 2017.
  • As I mentioned before, AppCoins will be rolled out as a completed project to 200M users by the end of 2018 whether you want to believe it or not (barring a total catastrophe, of course). Aptoide store users may not even know that they're using a cryptocurrency.
  • AppCoins may be the first real "mainstream" cryptocurrency (by definition of the high number of users with little to no technical knowledge or grasp of blockchain).
  • There will be 200 million users' app transactions on the blockchain. This is a huge step in the right direction for blockchain and cryptocurrency regardless of which coin you support. Rising tides raise all ships.
Needless to say, I think that Aptoide and AppCoins is a project to be excited about regardless of whether you're a cryptocurrency trader or completely uninvolved with the cryptocurrency space. Cryptocurrency is going mainstream this year!
To avoid confusion since Coinmarketcap has APPC listed incorrectly, here is the current accurate financial information. People are going to ask anyway so I would rather supply the correct information:
Circulating supply= 98M APPC Total supply= 246M APPC Coin Price = $2.53 ICO Price = $0.10 Market Cap (CS x P) = $247,940,000 Days on Exchange (Binance) = 7
Thank you for reading!
submitted by censorship_notifier to noncensored_bitcoin [link] [comments]

O que é o Blockchain (#1) - Código Hash The Bitcoin Group #233 - Binance Trouble - John Nash ... Binance Launches Crypto Mining Pool Amid Centralization Concerns BINANCE  Einführung und Anleitung  Deutsch Binance With Credit Card, Coinbase New York Coins, Bitcoin Hash Rate & Bitcoin Price Recovery O que é um hash? (bitcoin / blockchain) - YouTube BREAKING NEWS!!! PROOF: BITCOIN MANIPULATED BY BINANCE AND COINBASE!! IS $8'500 THE TARGET!!? MASSIMI HASH RATE BTC \ BINANCE USA FONDAMENTALE PER LE ALTCOIN Binance New Lending Coins, ETH On BitPay, Fiat To Crypto & Bitcoin ETF SEC Report Binance para iniciantes / Saques e Depósitos (Bitcoin ...

Hash Watch: Bitcoin Cash Miners Begin Signaling Node Implementations . There’s 88 days left until the Bitcoin Cash upgrade scheduled for November 15, 2020, and the community has been watching ... Exemple de fonction de hachage. Nous allons observer directement les qualités de la fonction de hachage qui est probablement la plus connue à ce jour : la fonction SHA-256, mise au point par la NSA, agence gouvernementale étasunienne bien connue. Et puisqu’il est question de hachage, sel et poivre, nous allons calculer l’empreinte du mot bœuf. Bitcoin is the currency of the Internet. A distributed, worldwide, decentralized digital money. Unlike traditional currencies such as dollars, bitcoins are issued and managed without the need for any central authority whatsoever. Learn more about Bitcoin, Bitcoin Cash, cryptocurrency, and more. Hash Watch: Bitcoin Cash Services Reveal Contingency Plans for Upcoming Fork The Bitcoin Cash blockchain is set to upgrade on Sunday, November 15 and it’s still expected that the network will ... Teams. Q&A for Work. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. BitCoin verwendet den SHA-256 Hash-Algorithmus, um nachweislich “zufällige” Zahlen in einer Weise zu erzeugen, die einen vorhersehbaren CPU-Aufwand erfordert. Das Erzeugen eines SHA-256-Hash mit einem Wert kleiner als das aktuelle Ziel löst einen Block auf und gewinnt einige Coins. Hash-Rate oder Hash-Power ist etwas sehr Kritisches und integraler Bestandteil von Bitcoins Netzwerk aus ... According to Binance Research, ... 2.3.1 Immediate post-fork aftermath: the Bitcoin Cash “hash-war” The hard fork of Bitcoin Cash, which occurred at block 609,136 10, led to a hashrate competition (referred to as “hash-war”) to determine what “Bitcoin Cash version” was the most legitimate one. This war was costly and mostly non-economical as it resulted in an estimated loss of ... The target is a number that is reset periodically. To successfully mine a block, the miner must find a hash lower than this number. We can use a simple example here. Suppose that we have the term “binance,” and we want to produce a SHA256 hash whose first character is “0”. We can keep adding numbers to “binance” (i.e., “binance1 ... Introduction for Binance Smart Pool . Smart Pool is a service that enables the user to get higher profit by auto-switching hash rate to mine different currencies with the same algorithm. Binance Smart Pool is supporting the SHA256 algorithm and the hash rate of users can be switched among BTC, BCH, and BSV automatically. Blockchains machen starken Gebrauch von Hash-Funktionen und Kryptographie, die vor der Veröffentlichung von Bitcoin jahrzehntelang existierten. Interessanterweise konnte die Struktur der Blockchain bis in die frühen 1990er Jahre zurückverfolgt werden, obwohl sie nur für die Zeitstempelung von Dokumenten verwendet wurde, so dass sie später nicht mehr verändert werden konnten.

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O que é o Blockchain (#1) - Código Hash

Nesta apresentação você vai entender o que é um hash. https://tribocrypto.com/t/video-o-que-e-um-hash/134 Hashes criptográficos são utilizados dentro da bloc... #criptovalute #accriptovalute #bitcoin come funziona #btc #altcoin #binance #investire #guadagnare #il bitcoin L'hash rate del BTC ha raggiunto nuovi massimi è un buon segno ? Binance USA per ... Binance With Credit Card, Coinbase New York Coins, Bitcoin Hash Rate & Bitcoin Price Recovery The Modern Investor. Loading... Unsubscribe from The Modern Investor? Cancel Unsubscribe. Working ... Off The Chain #238: PlanB on Why Bitcoin’s Stock-To-Flow Model Is Becoming More Accurate Over Time - Duration: 1:05:59. Anthony Pompliano 41,748 views 1:05:59 Binance Pool has received mixed responses from the crypto community, with some commentators expressing concerns that Binance's pool will result in a further centralization of Bitcoin ( BTC ) hash ... #bitcoin #twitter #crypto #interest #stockmarket #recession #bearmarket #bullmarket #davincij15 #mmcrypto #btc #bitcoinprice #bitcointoday #crash #economy #inflation #ecb #fed #federalreserve # ... Nesse vídeo você aprenderá a realizar depósitos e saques na binance , acho que era isso , pronto falei . https://www.binance.com/?ref=10273283 WCN T-Shirts: http://worldcryptonetwork.store/ Donate Bitcoin: 3NqhJSAikoFiYmZm3ACGzdw9Lr86ZiLT7K Join our New Patreon: https://www.patreon.com/wcn Subscribe... Vídeo #1 da série "O que é o Blockchain", sobre o código HASH, um dos principais constituintes da tecnologia do Blockchain. Existem muitos videos sobre bitcoins e outras criptomoedas mas ... Binance findest du hier - https://goo.gl/86HNDK Krypto verstehen lernen - https://goo.gl/hGPpnE Bitcoin.de Wallet - https://goo.gl/s6wMpq Folge mir auf T...

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