Proof of Burn Explained Binance Academy - Bitcoin Exchange

Let's discuss some of the issues with Nano

Let's talk about some of Nano's biggest issues. I also made a video about this topic, available here: https://youtu.be/d9yb9ifurbg.
00:12 Spam
Issues
Potential Mitigations & Outstanding Issues
01:58 Privacy
Issues
  • Nano has no privacy. It is pseudonymous (like Bitcoin), not anonymous.
Potential Mitigations & Outstanding Issues & Outstanding Issues*
  • Second layer solutions like mixers can help, but some argue that isn't enough privacy.
  • The current protocol design + the computational overhead of privacy does not allow Nano to implement first layer privacy without compromising it's other features (fast, feeless, and scalable transactions).
02:56 Decentralization
Issues
  • Nano is currently not as decentralized as it could be. ~25% of the voting weight is held by Binance.
  • Users must choose representatives, and users don't always choose the best ones (or never choose).
Potential Mitigations & Outstanding Issues
  • Currently 4 unrelated parties (who all have a verifiable interest in keeping the network running) would have to work together to attack the network
  • Unlike Bitcoin, there is no mining or fees in Nano. This means that there is not a strong incentive for emergent centralization from profit maximization and economies of scale. We've seen this firsthand, as Nano's decentralization has increased over time.
  • Nano representative percentages are not that far off from Bitcoin mining pool percentages.
  • In Nano, voting weight can be remotely re-delegated to anyone at any time. This differs from Bitcoin, where consensus is controlled by miners and requires significant hardware investment.
  • The cost of a 51% attack scales with the market cap of Nano.
06:49 Marketing & adoption
Issues
  • The best technology doesn't always win. If no one knows about or uses Nano, it will die.
Potential Mitigations & Outstanding Issues
  • I would argue that the best technology typically does win, but it needs to be best in every way (price, speed, accessbility, etc). Nano is currently in a good place if you agree with that argument.
  • Bitcoin started small, and didn't spend money on marketing. It takes time to build a community.
  • The developers have said they will market more once the protocol is where they want it to be (v20 or v21?).
  • Community marketing initiatives have started to form organically (e.g. Twitter campaigns, YouTube ads, etc).
  • Marketing and adoption is a very difficult problem to solve, especially when you don't have first mover advantage or consistent cashflow.
08:07 Small developer fund
Issues
  • The developer fund only has 3 million NANO left (~$4MM), what happens after that?
Potential Mitigations & Outstanding Issues
  • The goal for Nano is to be an Internet RFC like TCP/IP or SMTP - development naturally slows down when the protocol is in a good place.
  • Nano development is completely open source, so anyone can participate. Multiple developers are now familiar with the Nano protocol.
  • Businesses and whales that benefit from Nano (exchanges, remittances, merchant services, etc) are incentivized to keep the protocol developed and running.
  • The developer fund was only ~5% of the supply - compare that to some of the other major cryptocurrencies.
10:08 Node incentives
Issues
  • There are no transaction fees, why would people run nodes to keep the network running?
Potential Mitigations & Outstanding Issues
  • The cost of consensus is so low in Nano that the benefits of the network itself are the incentive: decentralized money with 0 transaction fees that can be sent anywhere in the world nearly instantly. Similar to TCP/IP, email servers, and http servers. Just like Bitcoin full nodes.
  • Paying $50-$100 a month for a high-end node is a lot cheaper for merchants than paying 1-3% in total sales.
  • Businesses and whales that benefit from Nano (exchanges, remittances, merchant services, etc) are incentivized to keep the protocol developed and running.
11:58 No smart contracts
Issues
  • Nano doesn't support smart contracts.
Potential Mitigations & Outstanding Issues
  • Nano's sole goal is to be the most efficient peer-to-peer value transfer protocol possible. Adding smart contracts makes keeping Nano feeless, fast, and decentralized much more difficult.
  • Other solutions (e.g. Ethereum) exist for creating and enforcing smart contracts.
  • Code can still interact with Nano, but not on the first layer in a decentralized matter.
  • Real world smart contract adoption and usage is pretty limited at the moment, but that might not always be the case.
13:20 Price stability
Issues
  • Why would anyone accept or spend Nano if the price fluctuates so much?
  • Why wouldn't people just use a stablecoin version of Nano for sending and receiving money?
Potential Mitigations & Outstanding Issues
  • With good fiat gateways (stable, low fees, etc), you can always buy back the fiat equivalent of what you've spent.
  • The hope is that with enough adoption, people and businesses will eventually skip the fiat conversion and use Nano directly.
  • Because Nano is so fast, volatility is less of an issue. Transactions are confirmed in <10 seconds, and prices change less in that timeframe (vs 10 minutes to hours for Bitcoin).
  • Stablecoins reintroduce trust. Stable against what? Who controls the supply, and how do you get people to adopt them? What happens if the assets they're stable against fail? Nano is pure supply and demand.
  • With worldwide adoption, the market capitalization of Nano would be in the trillions. If that happens, even millions of dollars won't move the price significantly.
15:06 Deflation
Issues
  • Nano's current supply == max supply. Why would people spend Nano today if it could be worth more tomorrow?
  • What happens to principal representatives and voting weight as private keys are lost? How do you know keys are lost?
Potential Mitigations & Outstanding Issues
  • Nano is extremely divisible. 1 NANO is 1030 raw. Since there are no transaction fees, smaller and smaller amounts of Nano could be used to transact, even if the market cap reaches trillions.
  • People will always buy things they need (food, housing, etc).
  • I'm not sure what the plan is to adjust for lost keys. Probably requires more discussion.
Long-term Scalability
Issue
  • Current node software and hardware cannot handle thousands of TPS (low-end nodes fall behind at even 50 TPS).
  • The more representatives that exist, the more vote traffic is required (network bandwidth).
  • Low-end nodes currently slow down the network significantly. Principal representatives waste their resources constantly bootstrapping these weak nodes during network saturation.
Potential Mitigations & Outstanding Issues
  • Even as is, Nano can comfortably handle 50 TPS average - which is roughly the amount of transactions per day PayPal was doing in 2011 with nearly 100 million users.
  • Network bandwidth increases 50% a year.
  • There are some discussions of prioritizing bootstrapping by vote weight to limit the impact of weak nodes.
  • Since Nano uses an account balance system, pruning could drastically reduce storage requirements. You only need current state to keep the network running, not the full transaction history.
  • In the future, vote stapling could drastically reduce bandwidth usage by collecting all representative signatures up front and then only sharing that single aggregate signature.
  • Nano has no artificial protocol-based limits (e.g. block sizes or block times). It scales with hardware.
Obviously there is still a lot of work to be done in some areas, but overall I think Nano is a good place. For people that aren't Nano fans, what are your biggest concerns?
submitted by Qwahzi to CryptoCurrency [link] [comments]

What are Nano's biggest issues? Let's talk about it!

Let's talk about some of Nano's biggest issues. I also made a video about this topic, available here: https://youtu.be/d9yb9ifurbg.
00:12 Spam
Issues
Potential Mitigations & Outstanding Issues
01:58 Privacy
Issues
  • Nano has no privacy. It is pseudonymous (like Bitcoin), not anonymous.
Potential Mitigations & Outstanding Issues & Outstanding Issues*
  • Second layer solutions like mixers can help, but some argue that isn't enough privacy.
  • The current protocol design + the computational overhead of privacy does not allow Nano to implement first layer privacy without compromising it's other features (fast, feeless, and scalable transactions).
02:56 Decentralization
Issues
  • Nano is currently not as decentralized as it could be. ~25% of the voting weight is held by Binance.
  • Users must choose representatives, and users don't always choose the best ones (or never choose).
Potential Mitigations & Outstanding Issues
  • Currently 4 unrelated parties (who all have a verifiable interest in keeping the network running) would have to work together to attack the network
  • Unlike Bitcoin, there is no mining or fees in Nano. This means that there is not a strong incentive for emergent centralization from profit maximization and economies of scale. We've seen this firsthand, as Nano's decentralization has increased over time.
  • Nano representative percentages are not that far off from Bitcoin mining pool percentages.
  • In Nano, voting weight can be remotely re-delegated to anyone at any time. This differs from Bitcoin, where consensus is controlled by miners and requires significant hardware investment.
  • The cost of a 51% attack scales with the market cap of Nano.
06:49 Marketing & adoption
Issues
  • The best technology doesn't always win. If no one knows about or uses Nano, it will die.
Potential Mitigations & Outstanding Issues
  • I would argue that the best technology typically does win, but it needs to be best in every way (price, speed, accessbility, etc). Nano is currently in a good place if you agree with that argument.
  • Bitcoin started small, and didn't spend money on marketing. It takes time to build a community.
  • The developers have said they will market more once the protocol is where they want it to be (v20 or v21?).
  • Community marketing initiatives have started to form organically (e.g. Twitter campaigns, YouTube ads, etc).
  • Marketing and adoption is a very difficult problem to solve, especially when you don't have first mover advantage or consistent cashflow.
08:07 Small developer fund
Issues
  • The developer fund only has 3 million NANO left (~$4MM), what happens after that?
Potential Mitigations & Outstanding Issues
  • The goal for Nano is to be an Internet RFC like TCP/IP or SMTP - development naturally slows down when the protocol is in a good place.
  • Nano development is completely open source, so anyone can participate. Multiple developers are now familiar with the Nano protocol.
  • Businesses and whales that benefit from Nano (exchanges, remittances, merchant services, etc) are incentivized to keep the protocol developed and running.
  • The developer fund was only ~5% of the supply - compare that to some of the other major cryptocurrencies.
10:08 Node incentives
Issues
  • There are no transaction fees, why would people run nodes to keep the network running?
Potential Mitigations & Outstanding Issues
  • The cost of consensus is so low in Nano that the benefits of the network itself are the incentive: decentralized money with 0 transaction fees that can be sent anywhere in the world nearly instantly.
  • Paying $50-$100 a month for a high-end node is a lot cheaper for merchants than paying 1-3% in total sales.
  • Businesses and whales that benefit from Nano (exchanges, remittances, merchant services, etc) are incentivized to keep the protocol developed and running.
11:58 No smart contracts
Issues
  • Nano doesn't support smart contracts.
Potential Mitigations & Outstanding Issues
  • Nano's sole goal is to be the most efficient peer-to-peer value transfer protocol possible. Adding smart contracts makes keeping Nano feeless, fast, and decentralized much more difficult.
  • Other solutions (e.g. Ethereum) exist for creating and enforcing smart contracts.
  • Code can still interact with Nano, but not on the first layer in a decentralized matter.
  • Real world smart contract adoption and usage is pretty limited at the moment, but that might not always be the case.
13:20 Price stability
Issues
  • Why would anyone accept or spend Nano if the price fluctuates so much?
  • Why wouldn't people just use a stablecoin version of Nano for sending and receiving money?
Potential Mitigations & Outstanding Issues
  • With good fiat gateways (stable, low fees, etc), you can always buy back the fiat equivalent of what you've spent.
  • The hope is that with enough adoption, people and businesses will eventually skip the fiat conversion and use Nano directly.
  • Because Nano is so fast, volatility is less of an issue. Transactions are confirmed in <10 seconds, and prices change less in that timeframe (vs 10 minutes to hours for Bitcoin).
  • Stablecoins reintroduce trust. Stable against what? Who controls the supply, and how do you get people to adopt them? What happens if the assets they're stable against fail? Nano is pure supply and demand.
  • With worldwide adoption, the market capitalization of Nano would be in the trillions. If that happens, even millions of dollars won't move the price significantly.
15:06 Deflation
Issues
  • Nano's current supply == max supply. Why would people spend Nano today if it could be worth more tomorrow?
  • What happens to principal representatives and voting weight as private keys are lost? How do you know keys are lost?
Potential Mitigations & Outstanding Issues
  • Nano is extremely divisible. 1 NANO is 1030 raw. Since there are no transaction fees, smaller and smaller amounts of Nano could be used to transact, even if the market cap reaches trillions.
  • People will always buy things they need (food, housing, etc).
  • I'm not sure what the plan is to adjust for lost keys. Probably requires more discussion.
Long-term Scalability
Issue
  • Current node software and hardware cannot handle thousands of TPS (low-end nodes fall behind at even 50 TPS).
  • The more representatives that exist, the more vote traffic is required (network bandwidth).
  • Low-end nodes currently slow down the network significantly. Principal representatives waste their resources constantly bootstrapping these weak nodes during network saturation.
Potential Mitigations & Outstanding Issues
  • Even as is, Nano can comfortably handle 50 TPS average - which is roughly the amount of transactions per day PayPal was doing in 2011 with nearly 100 million users.
  • Network bandwidth increases 50% a year.
  • There are some discussions of prioritizing bootstrapping by vote weight to limit the impact of weak nodes.
  • Since Nano uses an account balance system, pruning could drastically reduce storage requirements. You only need current state to keep the network running, not the full transaction history.
  • In the future, vote stapling could drastically reduce bandwidth usage by collecting all representative signatures up front and then only sharing that single aggregate signature.
  • Nano has no artificial protocol-based limits (e.g. block sizes or block times). It scales with hardware.
submitted by Qwahzi to nanocurrency [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]

My attempt at an ELI5 for cryptocurrency to help my friends.

This is a long one so fair warning and no there is no tl;dr. I've only been at this for about 6 months and worked up this paper the other day for my friends who are interested but know very little about this. Hopefully whoever reads this can make in corrections as I am far from an expert.
Blockchain
Cryptocurrency, Bitcoin, Ether are all blockchains. Blockchains are basically a spreadsheet (LEDGER) that is duplicated multiple times across a network and updated regularly simultaneously. There is no centralized version of this ledger. It is hosted simultaneously by thousands/millions of computers. These ledgers will update on their own, Bitcoin as an example automatically checks itself every 10 minutes. Each of these 10-minute increment of transactions (in bitcoins case transactions would be sending or receiving bitcoins from one person to another for goods or services) are called BLOCKS. For these blocks to be confirmed, accepted, and updated to the ledger nodes are required.
Nodes (Mining/Forging)
A node is a computer running the blockchain software on the network. The blockchain software will automatically download the entire ledger of all transactions since its inception. At regular intervals, the software will take the transactions of a block (data on the ledger) and convert them into a mathematical puzzle to be solved by randomly chosen nodes (MINING). Mining requires powerful processors (typically GPUs) and substantial quantities of energy to receive mined tokens profitably. When a specific number of nodes solve the puzzle with the same answer they are basically confirming that the data on the block is accurate as multiple independent nodes found the same answer. When confirmed, the block gets added to the previous blocks making a chain of blocks aka a blockchain. As an incentive to run your computer as a node you are rewarded with TOKENS. If a single person or group of people wanted to manipulate the ledger, the amount of machinery and electricity used to achieve the majority of miners thus allowing you to manipulate the ledger is so exponentially expensive that it serves no reasonable purpose. This is an example of a Proof of Work Blockchain System (computer solves puzzle and rewarded with tokens)
Tokens
Tokens are part of the core of the blockchain. They are an incentive to validate transactions and create blocks. They gain intrinsic value based on the blockchain they are associated with. Some blockchains grant token holder’s different abilities. With Bitcoin, tokens are needed to pay for transaction fees. Others allow voting rights on how certain blockchain functions are managed. There is a limited amount of Bitcoin that will ever be released to nodes (21 million expected to be all be released by 2033) which also keep inflation from being a problem. Blockchains can create their platform with whatever number of tokens they would like and release them or create means to mine them as they see fit. Essentially, as with any other fiat money (currency that a government has declared to be legal tender NOT backed by a physical commodity), as adoption and trust increases the value of the token will increase. If most people accept Bitcoin for services and stores accept Bitcoin for goods than it is as good as the next currency.
Wallets
Whether you mine for tokens, are paid in tokens for goods or services or purchase tokens from a person or currency exchange you need a place to store them securely and a way to send and receive them. Cryptocurrency Wallets don’t store currency, they hold your public and private keys that interface with the blockchain so you can access your balance, send money and manage your funds. The public key allows others to send money to the public key only. A wallet that is "offline" (see Hardware or Paper below) cannot access funds or send money unless it is accessed with another form of wallet, either desktop, online, or mobile.
1) Desktop Wallet - Installed on your computer and are only accessible from that SINGLE computer. Very secure but if someone hacks your computer you are exposed. 2) Online Wallet - Run remotely (cloud based) and are far more convenient to access but make them more vulnerable as they are controlled by a third party and are also vulnerable to hacking attacks. Exchange wallets are online wallets but you are not in control of the private key. View it as a wallet that is lended to you so you can trade. The wallet is technically not yours. 3) Mobile - Ran on an app and are useful as they can be used anywhere including retail stores 4) Hardware - Private keys are stored on a tangible device like a USB drive. They can make transactions online but they are stored offline. Compatible with web interfaces and support many but not all currencies. To use, plug into a computer, enter a pin, send currency and confirm. Safest form of storage. 5) Paper - Basically a physical printout of your private and public keys. It is not stored online anywhere and the only way transactions can happen is if you transfer money with the help of an Online wallet.
Example of a Public Key = 1A684DbsHQKPVCWgaUsYdF4uQGwTiA9BFT Example of a Private Key = E9873D79C6D87DC0FB6A5778633389F4453213303DA61F20BD67FC233AA33262
Most wallets provide a Recovery Mnemonic Passcode that is a series of words (typically 12 to 24 words) in a specific order. If you lose your login information for your wallet you can supply the mnemonic passcode and retrieve your lost login information. If you lose your login information and your mnemonic passcode your wallet will be inaccessible and your tokens are lost to you. The above basically describes a first generation Blockchain Cryptocurrency such as Bitcoin. It is used basically as currency with no centralized entity regulating the release of additional currency and keeping the ledger of where the money is going secure and extremely safe from manipulation.
Second Generation Blockchain
The second generation blockchains sprung out of this environment with something more valuable. Utilizing the blockchain system to allow applications to be ran on top of a decentralized secure system. Instead of just recording transactions, contracts could be transmitted the same way. More complex transactions (SMART CONTRACTS) allow for things such as: - Funds to be spent only when a required percentage of people agree - Manage agreements between users (such as insurance) - Provide utility to other contracts - Store information about an application such as domain registration information or membership records This basically can allow applications to be ran on top of the blockchain system. This can cut out the middleman for many real-world applications (mortgages, banking, communications, security confirmations etc.)
Proof of Work/Proof of Stake
As I mentioned earlier, Proof of Work (PoW) requires nodes to solve a mathematical puzzle which is rewarded with tokens. Proof of Stake (PoS) is different, the tokens with proof of stake systems are pre-mined meaning they are all created when the blockchain system is created. Blocks are not verified by the typical method. The block validator uses the blockchain software to stake their tokens and are chosen based on specific factors depending on how many tokens the person holds and for how long. Depending on how many tokens they hold will restrict the quantity of blocks they can validate. If they own more they can validate more often but all validators will be chosen randomly keeping the rewards fairly distributed (unlike PoW which typically reward the first completed.) The blockchain still requires a mathematical puzzle to be solved but it is much easier than PoW requiring far less time and energy. If the blockchain has premined all of their tokens then new tokens cannot be mined for rewards in PoS. The reward for staking your tokens to be a validator is a portion of the transaction fee that is charged as part of normal transactions on the blockchain. That is why PoS miners are called forgers. If manipulation is attempted than their stake can be taken from their wallet adding more motivation to prevent data manipulation.
Fork
Some cryptocurrencies may need to update or upgrade the coding of their blockchain software. When this happens usually a fork occurs. This basically means the cryptocurrency splits into two separate cryptocurrencies. Because the nature of blockchain technology, they are decentralized and autonomous so the older version cannot be deleted or removed. If people choose to continue using the old version they can. For mining/forging purposes the nodes will need to choose which they will mine/forge and download the blockchain software on their computer to proceed. When the fork occurs, anyone holding tokens in the original currency will be given the same number of tokens in the forked currency. (When Bitcoin forked to Bitcoin Cash, anyone holding x amount of Bitcoin would receive a new wallet for Bitcoin Cash also containing x amount of Bitcoin Cash.) This is called a Hard Fork and all previous transactions are made invalid. There are also Soft Forks, in this case it is backwards compatible and all previous transactions are valid. This can result in two currencies but in most cases, it doesn’t as it is usually accepted by most miners/forgers because it is backwards compatible.
Exchanges
Online currency exchanges allow you to buy, sell or exchange fiat money (USD, EUR, etc) with digital currencies or in most cases digital currencies for other digital currencies. There are a large variety of different exchanges that are operated in multiple countries but there are around a dozen that the majority of cryptocurrency trading volume are present on. Not all cryptocurrencies will be listed on all exchanges, some have specific prerequisites to be listed on their exchange and there may be fees associated as well. Once your account is set up you will have a list of all available cryptocurrencies to trade. Each currency will have an associated online wallet with the public key address allowing you to send that specific currency to that wallet. (Many exchanges are having delayed or canceled identity verification, currency transfers and lack sufficient customer support due to the influx of new traders) Examples of top exchanges: 1) Coinbase (trades fiat) 2) GDAX (trades fiat) 3) Gemini (trades fiat) 4) Changelly (trades fiat) 5) Bittrex 6) Binance 7) HitBTC 8) EtherDelta 9) Bitfinex 10) Kraken 11) Bithumb 12) Bitstamp 13) Poloniex 14) OKEx
Sending/Receiving Tokens
All wallets have the ability to send digital currency to other wallets. The function is relatively easy, make sure the currency you are sending is going to the appropriate wallet for that currency. Ethereum tokens cannot be sent to a Bitcoin wallet for example. (The tokens aren’t actually moving location; the list of transactions/ownership is what is stored in the wallet). Triple check the wallet private key you are sending the tokens to. If you type the wrong address the tokens will be lost in nearly all incidents. Some mobile wallets allow you to scan a QR code that will automatically enter the public key rather than copying/pasting or typing out the public key.
Taxes
As of January 1, 2018 it appears that taxing on digital currency has changed. Every trade between any digital currencies (Bitcoin to Ether, Ether to Litecoin etc) will be a taxable transaction. If you hold the currency for longer than one year than you will pay capital gain tax when it is traded or sold (15%-20%) and if you sell or trade in less than a year you will have to add the profit to your taxable income to adjust your tax bracket.
Altcoins
Altcoins are basically any coin that is not Bitcoin. Most cryptocurrencies do not have a native blockchain (their own independent dedicated blockchain). Bitcoin, Ether, Ripple, Waves, NXT, Cardano all have their own native blockchain. Many other cryptocurrencies run on other cryptocurrency’s blockchains. Litecoin runs on Bitcoins blockchain, hundreds run on the Ethereum blockchain. These currencies act as smart contracts running on the adopted blockchain.
DApps (Decentralized Applications)
For a blockchain application to be considered a DApp it must be 1) Open source, code available to all 2) Decentralized, uses blockchain cryptographic tech 3) Incentive, must have tokens to fuel itself 4) Algorithm/Protocol, generates tokens and has a built-in consensus mechanism (mining/forging.)
There are 3 types of DApps, each basically piggybacks off the platform of the previous Type 1 – Have their own blockchain (like bitcoin) Type 2 – Use the blockchain of Type 1 DApps Type 3 – Use the protocol of Type 2 DApps
ICO (Initial Coin Offering)
Much like an IPO (Initial Public Offering) that offers stock in a private company to the public, an ICO raises money for new Cryptocurrency ventures. Typically, a minimum investment is required in the form of a cryptocurrency such as Bitcoin or Ether and the investor is given tokens of the cryptocurrency at a reduced cost. Due to the fact that ICO’s are so new, government agencies have not begun regulating these ventures making them extremely risky as anyone with a competent coder can create and market a cryptocurrency that can be used to swindle investors who aren’t cautious. The US government no longer allows its citizens to participate in ICO’s and if you are using a computer with an IP address located in the United States, ICO’s websites will not allow you to invest.
Research
1) Whitepapers – Each cryptocurrency will have their own dedicated websites and most will have a whitepaper that has a description of what their cryptocurrency is designed to do. 2) Roadmaps – Also on each cryptocurrency’s website, they tend to have a roadmap or timeline as to when they are planning to complete certain milestones be it added features to the blockchain or wallet or any other important events. 3) Coinmarketcap.com – List of every available cryptocurrency, the exchanges they trade on, market cap, trade volume, available tokens, newly created tokens etc. 4) Reddit.com (cryptocurrency subreddit) – Subreddits focused on cryptocurrency as well as specific subreddits focused on individual cryptocurrencies. Be cautious as many people on these sites are uninformed and/or are trying to manipulate the market by fooling others to buy or sell based on fraudulent information. 5) Bitcointalk.org – Forums specific to individual cryptocurrencies. There is a lot of self-marketing (bounties) on this site. Take what they say with a grain of salt 6) TwitteFacebook (Social Media) – Many times news from team members or the cryptocurrency’s social media page will break news before it is listed on any of the above-mentioned outlets. Find out who is working for the cryptocurrency you are interested in and start following the team’s social media. Don’t forget to look at their linkedin accounts if available, previous employment and behavioral history to confirm they are competent. 7) Github - Code from projects can be uploaded here and reviewed for issues and revisions.
Common Terms/Slang
Shilling – covert advertising, personally endorsing a token so as to manipulate the price to either recoup a loss or increase gains on a token the individual owns. FUD – Fear, Uncertainty, Doubt; another method to manipulate the price of a token the person owns by making others second guess their investment decision on a specific token. FOMO – Fear Of Missing Out; buying a token (usually after the price has already increased) hoping they haven’t missed the majority of a price increase. Shitcoin – A cryptocurrency that has become worthless overtime or a scam operation. To the Moon – Massive increase in a token’s price.
I'm sure there are probably revisions to be done on this as I am still getting my head around all of the concepts. Any help to this would be appreciated.
submitted by Truantlife to CryptoCurrency [link] [comments]

Groestlcoin Release September 2018

Introduction

As always, the past 3 months since 22nd June have been crazy busy. The bears might still be around, but the show must go on and of course has not slowed the Groestlcoin development team in the slightest. Here’s a quick overview of what has already happened since the last release: - Integrated into the bitbns exchange, with the ability to buy Groestlcoin directly with the Indian Rupee. - Groestlcoin Rebrand Vote – Whilst there was much talk and push for a rebrand vote, the overall result was almost unanimously in favour of keeping our unique and conversation-starting name. With just 83 votes to Rebrand, and 2577 votes to No Rebrand. Thank you for all who voted, the funds raised are being used to fund ongoing hosting and development costs. - Integrated into the Cryptobridge exchange. Cryptobridge is a popular decentralised exchange where you always hold the private keys to your funds, only YOU have access to them. - Groestlcoin has been added to SimpleSwap – Groestlcoin can now be swapped with over 100 other cryptocurrencies, without signing up! - Groestlcoin has been added to UnoDax, one of the leading cryptocurrency exchanges in India, with TUSD, BTC and INR trading pairs. - Groestlcoin has been added to SwapLab.cc, where you can buy Groestlcoin using Bitcoin and over 50 other altcoins. Purchasing with VISA/Mastercard is coming VERY SOON. Discussed later: - Groestlcoin has been listed on #3 largest exchange in the world on volume, Huobi Global! More on this to come further on in the announcements. - Groestlcoin has been added to the Guarda Multi-Currency Wallet. - Groestlcoin has been added to Melis Multi-Device, Multi-Account, Multi-Platform, Multi-Signature advanced wallet! Already this list is far more than most other cryptocurrencies have achieved in the past 3 months. But this is just the tip of the iceberg of what has been developed.

What's been Happening?

GRSPay Released

We are so excited for this, that it has it's own separate reddit thread. Head over there now at https://www.reddit.com/groestlcoin/comments/9ikr5m/groestlcoin_releases_grspay/? to see more on this!
https://www.melis.io/assets/logo-navbar-4b6f0d372f15b2446d3fa4c68f346e4fb08ee113941186cee58fd6135f3f8b7d.svg

Melis Wallet

The the most advanced wallet for Bitcoin, Bitcoin Cash, Litecoin and now Groestlcoin.
With Melis you have the complete control of your bitcoins and private keys, you can define spending limits policies and make use of two or more factors authentication. Melis is open source, published on GitHub.

How Melis Works?

You can create as many accounts as you want. An account is a part of your wallet that can be customised to your requirements. You can choose how many co-signers are required to spend funds. The accounts are completely independent and act like separate wallets from each other but can be accessed via the same details. A core feature of Melis is the ability to set a ‘primary’ device. With this you can set an account as ‘Secure’ so it is only viewable (and accessible at all) from the Primary device. You can have a savings account hidden from the outside world whilst also having your ‘spending’ funds available on the go. With Melis you can create a multi-signature account between N people, where up to N signatures are required to sign a transaction, choosing if any of those should be mandatory.
Core Features:
https://guarda.co/assets/images/1PGo4ID.svg?1537791124643

Guarda Wallet

Safer than ever! Desktop Light Wallet - Anonymous and fast!
With Guarda Multi-currency Desktop Light Wallet you don’t need to register. Guarda has no access to your private keys or funds. You can receive, send, store, buy and exchange cryptocurrencies in complete anonymity and safety. All these features are available on Linux, Windows or MacOS. Choose the one that suits you!
More info about Guarda wallet on www.guarda.co
https://holytransaction.com/images/logo.png

Integrated into HolyTransaction

What is HolyTransaction?

HolyTransaction gives users access to the crypto world with a universal cryptocurrency wallet and instant exchange.

Features

For more information, visit Holy Transaction here.
https://www.groestlcoin.org/wp-content/uploads/2018/09/next-grs-groestlcoin.jpg

Integrated into NEXT Wallet

What is NEXT?

NEXT is a modern, next-generation stylish open-source Desktop wallet.

Features

For more information, visit NextWallet here.
https://blockchainfinancial.com/mediaserve2018/09/admin-06143647-bcf_logo_vec_256x256.png

Integrated into Blockchain Financial

What is Blockchain Financial?

Blockchain Financial is a set of web based services for individuals and companies that want to make things happen with the Cryptocurrencies Ecosystem. - For those that don't know anything about cryptocurrencies, we offer tools that will let them receive, send and operate with an assortment of coins. - For those that are already riding the wave, we offer tools that will let them do all those things that they weren't able to do.

Blockchain Financials mission

We're not here to reinvent the wheel. We're here to make it run smoother for you, and we provide some of the most useful services you'll find on the internet, made in a way that is easy to understand and use on a daily basis. In short, we're a bunch of people that claim to be Crypto Evangelists. We strongly believe in cryptocurrencies, and our main promise is to push them up so more people get involved and take all the advantages they offer.

More information from Blockchain Financial

Back in 2014, the world was taken by storm when Facebook approved the first cryptocurrencies tipping apps. The first was for Dogecoin, and the second was for multiple coins.
The project was hosted on whitepuma.net, and persisted for almost two years, built up a massive user community and gave a home to Bitcoin, Litecoin, Dogecoin and dozens of other bitcoin-based altcoins.
After very active months, the tipping hype started to fade away. Then, the developers decided to jump into the next stage: bringing not only tipping, but also mining and a widget that could be embedded on websites to allow everyone to accept payments. Sadly, the work was never completed because the project started to require an unsustainable amount of resources. Then, in a painful decision, a shutdown was announced by December 2015.
A couple of months after whitepuma.net was closed, the source code was released by its creator as Open Source on GitHub. But it wasn't maintained.
Now, some of the original members of the dev and admin teams gathered up with a handful of the WhitePuma's elite users, and decided to make something good with the best pieces of the old source code. That, with fresh new ideas and the power of the BardCanvas engine, synthesized the core of Blockchain Financial.
More info about Blockchain Financial wallet on .
For more information, visit [Blockchain Financial](www.blockchainfinancial.com)
https://www.huobi.com/image/logo.aeb4723.svg

Groestlcoin Listed on Huobi

Who are Huobi?

Huobi was founded in China and is now based in Singapore, with offices in Hong Kong, South Korea, Japan and the North America, currently sitting #3 in volume on Coinmarketcap. Huobi is a great leap forward for our growing presence in Asia and we are very excited to be listed here!
You can find the official Huobi announcement here.

Groestlcoin Core v2.16.3 - Please Update ASAP

A new major Groestlcoin Core version 2.16.3 is now available for download which includes both a Denial of Service component and a critical inflation vulnerability, so it is recommended to upgrade to it if you are running a full Groestlcoin node or a local Groestlcoin Core wallet.
v2.16.3 is now the official release version of Groestlcoin Core. This is a new major version release with a very important security updates. It is recommended to upgrade to this version as soon as possible. Please stop running versions of Groestlcoin Core affected by CVE-2018-17144 ASAP: These are 2.13.3 and 2.16.0.
As a result in this, all exchanges and services have been asked to upgrade to this version, so please be patient if wallets go in to maintenance mode on these services.

What's new in version v2.16.3?

This is a major release of Groestlcoin Core fixing a Denial of Service component and a critical inflation vulnerability (https://nvd.nist.gov/vuln/detail/CVE-2018-17144) exploitable by miners that has been discovered in Groestlcoin Core version 2.13.3 and 2.16.0. It is recommended to upgrade to 2.16.3 as soon as possible. If you only occasionally run Groestlcoin Core, then it's not necessary to run out and upgrade it right this second. However, you should upgrade it before you next run it. If you know anyone who is running an older version, tell them to upgrade it ASAP. Stored funds are not at risk, and never were at risk. At this time we believe over half of the Groestlcoin hashrate has upgraded to patched nodes. We are unaware of any attempts to exploit this vulnerability. However, it still remains critical that affected users upgrade and apply the latest patches to ensure no possibility of large reorganizations, mining of invalid blocks, or acceptance of invalid transactions occurs.

The Technicals

In Groestlcoin Core 2.13.3, an optimization was added (Bitcoin Core PR #9049) which avoided a costly check during initial pre-relay block validation that multiple inputs within a single transaction did not spend the same input twice which was added in 2012 (Bitcoin Core PR #443). While the UTXO-updating logic has sufficient knowledge to check that such a condition is not violated in 2.13.3 it only did so in a sanity check assertion and not with full error handling (it did, however, fully handle this case twice in prior to 2.1.0.6). Thus, in Groestlcoin Core 2.13.3, any attempts to double-spend a transaction output within a single transaction inside of a block will result in an assertion failure and a crash, as was originally reported. In Groestlcoin Core 2.16.0, as a part of a larger redesign to simplify unspent transaction output tracking and correct a resource exhaustion attack the assertion was changed subtly. Instead of asserting that the output being marked spent was previously unspent, it only asserts that it exists. Thus, in Groestlcoin Core 2.16.0, any attempts to double-spend a transaction output within a single transaction inside of a block where the output being spent was created in the same block, the same assertion failure will occur. However, if the output being double-spent was created in a previous block, an entry will still remain in the CCoin map with the DIRTY flag set and having been marked as spent, resulting in no such assertion. This could allow a miner to inflate the supply of Groestlcoin as they would be then able to claim the value being spent twice.
Groestlcoin would like to publicly thank Reddit user u/Awemany for finding CVE-2018-17144 and reporting it (https://lists.linuxfoundation.org/pipermail/bitcoin-core-dev/2018-Septembe000064.html). You deserve gratitude and appreciation from cryptoworld, and you have ours. If you want to support him for his work, please consider donating to him on his bitcoin cash address: bitcoincash:qr5yuq3q40u7mxwqz6xvamkfj8tg45wyus7fhqzug5
http://i.imgur.com/3YhyNZK.png

Groestlcoin Electrum-GRS 3.2.2 - Ledger & Trezor Edition

What is Electrum-GRS?
Electrum-GRS is a lightweight "thin client" groestlcoin wallet Windows, MacOS and Linux based on a client-server protocol. Its main advantages over the original Groestlcoin client include support for multi-signature wallets and not requiring the download of the entire block chain.

Changes:

http://i.imgur.com/3YhyNZK.png

Electrum-GRS Mobile Android

What is Electrum-GRS Mobile?

Electrum-grs is a lightweight "thin client" groestlcoin wallet Android based on a client-server protocol. Its main advantages over the original Groestlcoin client include support for multi-signature wallets and not requiring the download of the entire block chain.

Changes

Groestlcoin EasyVanity Released

Groestlcoin EasyVanity is a Windows app is built from the ground-up in C# and makes it easier than ever before to create your very own bespoke Groestlcoin address(es), even whilst not connected to the internet! You can even generate multiple keys with the same prefix and leave it on overnight whilst your CPU or GPU collects and stores these addresses locally.
If you're tired of the random, cryptic addresses generated by regular groestlcoin clients, then Groestlcoin EasyVanity is the right choice for you to create a more personalized address.

Features

• Ability to continue finding keys after first one is found • Includes warning on startup if connected to the internet • Ability to output keys to a text file (And shows button to open that directory) • Ability to make your match case sensitive (Where possible) • Show and hide the private key with a simple toggle switch, and copy the private key straight to your clipboard • Show full output of commands • Includes statistics whilst the application is running • Ability to choose between Processor (CPU) and Graphics Card (GPU) • Automatically detects 32 or 64 bit systems • Features both a Light and Dark Material Design inspired Themes • EasyVanity's search is probabilistic, and the amount of time required to find a given pattern depends on how complex the pattern is, the speed of your computer, and whether you get lucky. • EasyVanity includes components to perform address searching on your CPU (vanitygen) and your OpenCL-compatible GPU (oclvanitygen). Both can be built from source, and both are included in the Windows binary package. • Prefixes are exact strings that must appear at the beginning of the address. When searching for prefixes, Easyvanity will ensure that the prefix is possible, and will provide a difficulty estimate. • The percentage displayed just shows how probable it is that a match would be found in the session so far. If it finds your address with 5% on the display, you are extremely lucky. If it finds your address with 92% on the display, you are unlucky. If you stop EasyVanity with 90% on the display, restart it, and it finds your address with 2% on the display, your first session was unlucky, but your second session was lucky. • EasyVanity uses the OpenSSL random number generator. This is the same RNG used by groestlcoin and a good number of HTTPS servers. It is regarded as well-scrutinized. Guessing the private key of an address found by EasyVanity will be no easier than guessing a private key created by groestlcoin itself. • To speed up address generation, EasyVanity uses the RNG to choose a private key, and literally increments the private key in a loop searching for a match. As long as the starting point is not disclosed, if a match is found, the private key will not be any easier to guess than if every private key tested were taken from the RNG. EasyVanity will also reload the private key from the RNG after 10,000,000 unsuccessful searches (100M for oclvanitygen), or when a match is found and multiple patterns are being searched for. • Free software - MIT. Anyone can audit the code. • Written in C# - The code is short, and easy to review.

Groestlcoin Sentinel (Android & Blackberry) – Mainnet + Testnet

What is Sentinel?

Groestlcoin Sentinel is the easiest and fastest way to track/receive/watch payments in your offline Groestlcoin Wallets. Groestlcoin Sentinel is compatible with any standard Groestlcoin address, BIP44 XPUB (Extended Public Key) BIP49 YPUB and BIP84 ZPUB
Groestlcoin Sentinel is a great solution for anyone who wants the convenience and utility of a hot wallet for receiving payments directly into their cold storage (or hardware wallets). Sentinel accepts XPUB's, YPUB'S, ZPUB's and individual Groestlcoin address. Once added you will be able to view balances, view transactions, and (in the case of XPUB's, YPUB's and ZPUB's) deterministically generate addresses for that particular wallet.

What's New?

The P2SH paperwallet supports creating P2SH paperwallets in bulk, keypair generation with QR codes and sweeping tool. Groestlcoin believes strongly in privacy, the live version does not collect and store IP or transaction data.
Changes
Features
The BECH32 paperwallet supports creating BECH32 paperwallets in bulk, keypair generation with QR codes and sweeping tool. Groestlcoin believes strongly in privacy, the live version does not collect and store IP or transaction data.
Features
![WebWallet](https://i.imgur.com/Z2oj7bj.png)

Groestlcoin Web Wallet Update 1.4

What is Groestlcoin Web Wallet?
Groestlcoin Webwallet is an open source, multisignature, HD Wallet and more! Webwallet is a a open source browser based Groestlcoin webwallet.
Webwallet is a playground for Groestlcoin in javascript to experiment with. It supports multisig, OP_HODL, RBF and many more. Groestlcoin believes strongly in privacy, the live version does not collect and store IP or transaction data.
Changes:
submitted by Yokomoko_Saleen to groestlcoin [link] [comments]

Is a central authority like a government required to ensure a transaction receiver received their purchase?

I know in the Bitcoin blockchain, receivership of Bitcoin (in whatever amount) is validated by the miners/cryptographic functions consensus, but that doesn't mean whatever was "purchased" by it (like an apple) can be validated to be received by the purchaser. I was speaking with someone today who mentioned that a central authority is required to insure that the purchaser receives the apple or receives a refund.
I honestly don't know how Bitcoin or any dApp (smart transaction) blockchain could validate that an apple or even any digital good was actually received by the "purchaser" (or even mailed/emailed to them), but it can record that at least an apple or digital good was bought. So the "trust" is then set on the receiver of the Bitcoin (or whatever coin) to provide the purchaser with the apple or digital good. I suppose if a digital string of characters is the purchased good, that could be in the purchaser's wallet and show that it was received, but I'm not sure that's something buyers would actually want (for privacy reasons).
I said that yes for physical items, no blockchain can prove an item was delivered (like say if USPS put shipping transactions on a blockchain, they could state in the transaction what was delivered, where, when, from who, and maybe even record a delivery signature, but that doesn't mean it was actually physically delivered), but that doesn't undermine the blockchain, as its trustless and the only trust that is expected or lost would be on the deliveresender of the apple. The record can't be changed, just a new record added correcting the previous record. He said blockchains aren't trustless, that we rely on the trust of the centralized nodes (I guess he meant the master nodes?), and that that's irrelevant anyways as they can't prove the apple was delivered.
So is he right that transactions using Bitcoin must rely on an outside centralized authority like Binance to ensure delivery of a purchased good? Or can blockchains be built in a way that at least ensures delivery of digital goods, even if they then would be publicly visible on the blockchain (or at least visible only to the wallet private key holder), or at least ensure a record of the delivery (like a picture)?
I don't think this argument invalidates the reason to have blockchain, but I certainly couldn't tell him it was better than any centralized authority he relies on, like the FDIC ensuring bank account (ironically of course banks and the government are both centralized).
submitted by kristoday to Bitcoin [link] [comments]

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