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Bullion (CBX) | Est 2013 | Masternodes Coming Soon!

Released in late June 2013, Bullion was designed primarily for the purpose of storing wealth. Bullion is the first to employ its pioneering Proof-of-Stake-Participation (PoSP) algorithm which has taken the strength of traditional proof-of-stake implementations, extreme energy efficiency, and injected revolutionary designs to configure the algorithm for maximum security and function.

What happens in case of a black swan event which makes miners leave? Would the network come to an halt? For how long? Would it ever find another block? /r/Bitcoin

What happens in case of a black swan event which makes miners leave? Would the network come to an halt? For how long? Would it ever find another block? /Bitcoin submitted by BitcoinAllBot to BitcoinAll [link] [comments]

Quick question: when finding a block, how long the miner restricted to sell/transfer the reward? /r/Bitcoin

Quick question: when finding a block, how long the miner restricted to sell/transfer the reward? /Bitcoin submitted by BitcoinAllBot to BitcoinAll [link] [comments]

Technical: The Path to Taproot Activation

Taproot! Everybody wants to have it, somebody wants to make it, nobody knows how to get it!
(If you are asking why everybody wants it, see: Technical: Taproot: Why Activate?)
(Pedants: I mostly elide over lockin times)
Briefly, Taproot is that neat new thing that gets us:
So yes, let's activate taproot!

The SegWit Wars

The biggest problem with activating Taproot is PTSD from the previous softfork, SegWit. Pieter Wuille, one of the authors of the current Taproot proposal, has consistently held the position that he will not discuss activation, and will accept whatever activation process is imposed on Taproot. Other developers have expressed similar opinions.
So what happened with SegWit activation that was so traumatic? SegWit used the BIP9 activation method. Let's dive into BIP9!

BIP9 Miner-Activated Soft Fork

Basically, BIP9 has a bunch of parameters:
Now there are other parameters (name, starttime) but they are not anywhere near as important as the above two.
A number that is not a parameter, is 95%. Basically, activation of a BIP9 softfork is considered as actually succeeding if at least 95% of blocks in the last 2 weeks had the specified bit in the nVersion set. If less than 95% had this bit set before the timeout, then the upgrade fails and never goes into the network. This is not a parameter: it is a constant defined by BIP9, and developers using BIP9 activation cannot change this.
So, first some simple questions and their answers:

The Great Battles of the SegWit Wars

SegWit not only fixed transaction malleability, it also created a practical softforkable blocksize increase that also rebalanced weights so that the cost of spending a UTXO is about the same as the cost of creating UTXOs (and spending UTXOs is "better" since it limits the size of the UTXO set that every fullnode has to maintain).
So SegWit was written, the activation was decided to be BIP9, and then.... miner signalling stalled at below 75%.
Thus were the Great SegWit Wars started.

BIP9 Feature Hostage

If you are a miner with at least 5% global hashpower, you can hold a BIP9-activated softfork hostage.
You might even secretly want the softfork to actually push through. But you might want to extract concession from the users and the developers. Like removing the halvening. Or raising or even removing the block size caps (which helps larger miners more than smaller miners, making it easier to become a bigger fish that eats all the smaller fishes). Or whatever.
With BIP9, you can hold the softfork hostage. You just hold out and refuse to signal. You tell everyone you will signal, if and only if certain concessions are given to you.
This ability by miners to hold a feature hostage was enabled because of the miner-exit allowed by the timeout on BIP9. Prior to that, miners were considered little more than expendable security guards, paid for the risk they take to secure the network, but not special in the grand scheme of Bitcoin.

Covert ASICBoost

ASICBoost was a novel way of optimizing SHA256 mining, by taking advantage of the structure of the 80-byte header that is hashed in order to perform proof-of-work. The details of ASICBoost are out-of-scope here but you can read about it elsewhere
Here is a short summary of the two types of ASICBoost, relevant to the activation discussion.
Now, "overt" means "obvious", while "covert" means hidden. Overt ASICBoost is obvious because nVersion bits that are not currently in use for BIP9 activations are usually 0 by default, so setting those bits to 1 makes it obvious that you are doing something weird (namely, Overt ASICBoost). Covert ASICBoost is non-obvious because the order of transactions in a block are up to the miner anyway, so the miner rearranging the transactions in order to get lower power consumption is not going to be detected.
Unfortunately, while Overt ASICBoost was compatible with SegWit, Covert ASICBoost was not. This is because, pre-SegWit, only the block header Merkle tree committed to the transaction ordering. However, with SegWit, another Merkle tree exists, which commits to transaction ordering as well. Covert ASICBoost would require more computation to manipulate two Merkle trees, obviating the power benefits of Covert ASICBoost anyway.
Now, miners want to use ASICBoost (indeed, about 60->70% of current miners probably use the Overt ASICBoost nowadays; if you have a Bitcoin fullnode running you will see the logs with lots of "60 of last 100 blocks had unexpected versions" which is exactly what you would see with the nVersion manipulation that Overt ASICBoost does). But remember: ASICBoost was, at around the time, a novel improvement. Not all miners had ASICBoost hardware. Those who did, did not want it known that they had ASICBoost hardware, and wanted to do Covert ASICBoost!
But Covert ASICBoost is incompatible with SegWit, because SegWit actually has two Merkle trees of transaction data, and Covert ASICBoost works by fudging around with transaction ordering in a block, and recomputing two Merkle Trees is more expensive than recomputing just one (and loses the ASICBoost advantage).
Of course, those miners that wanted Covert ASICBoost did not want to openly admit that they had ASICBoost hardware, they wanted to keep their advantage secret because miners are strongly competitive in a very tight market. And doing ASICBoost Covertly was just the ticket, but they could not work post-SegWit.
Fortunately, due to the BIP9 activation process, they could hold SegWit hostage while covertly taking advantage of Covert ASICBoost!

UASF: BIP148 and BIP8

When the incompatibility between Covert ASICBoost and SegWit was realized, still, activation of SegWit stalled, and miners were still not openly claiming that ASICBoost was related to non-activation of SegWit.
Eventually, a new proposal was created: BIP148. With this rule, 3 months before the end of the SegWit timeout, nodes would reject blocks that did not signal SegWit. Thus, 3 months before SegWit timeout, BIP148 would force activation of SegWit.
This proposal was not accepted by Bitcoin Core, due to the shortening of the timeout (it effectively times out 3 months before the initial SegWit timeout). Instead, a fork of Bitcoin Core was created which added the patch to comply with BIP148. This was claimed as a User Activated Soft Fork, UASF, since users could freely download the alternate fork rather than sticking with the developers of Bitcoin Core.
Now, BIP148 effectively is just a BIP9 activation, except at its (earlier) timeout, the new rules would be activated anyway (instead of the BIP9-mandated behavior that the upgrade is cancelled at the end of the timeout).
BIP148 was actually inspired by the BIP8 proposal (the link here is a historical version; BIP8 has been updated recently, precisely in preparation for Taproot activation). BIP8 is basically BIP9, but at the end of timeout, the softfork is activated anyway rather than cancelled.
This removed the ability of miners to hold the softfork hostage. At best, they can delay the activation, but not stop it entirely by holding out as in BIP9.
Of course, this implies risk that not all miners have upgraded before activation, leading to possible losses for SPV users, as well as again re-pressuring miners to signal activation, possibly without the miners actually upgrading their software to properly impose the new softfork rules.

BIP91, SegWit2X, and The Aftermath

BIP148 inspired countermeasures, possibly from the Covert ASiCBoost miners, possibly from concerned users who wanted to offer concessions to miners. To this day, the common name for BIP148 - UASF - remains an emotionally-charged rallying cry for parts of the Bitcoin community.
One of these was SegWit2X. This was brokered in a deal between some Bitcoin personalities at a conference in New York, and thus part of the so-called "New York Agreement" or NYA, another emotionally-charged acronym.
The text of the NYA was basically:
  1. Set up a new activation threshold at 80% signalled at bit 4 (vs bit 1 for SegWit).
    • When this 80% signalling was reached, miners would require that bit 1 for SegWit be signalled to achive the 95% activation needed for SegWit.
  2. If the bit 4 signalling reached 80%, increase the block weight limit from the SegWit 4000000 to the SegWit2X 8000000, 6 months after bit 1 activation.
The first item above was coded in BIP91.
Unfortunately, if you read the BIP91, independently of NYA, you might come to the conclusion that BIP91 was only about lowering the threshold to 80%. In particular, BIP91 never mentions anything about the second point above, it never mentions that bit 4 80% threshold would also signal for a later hardfork increase in weight limit.
Because of this, even though there are claims that NYA (SegWit2X) reached 80% dominance, a close reading of BIP91 shows that the 80% dominance was only for SegWit activation, without necessarily a later 2x capacity hardfork (SegWit2X).
This ambiguity of bit 4 (NYA says it includes a 2x capacity hardfork, BIP91 says it does not) has continued to be a thorn in blocksize debates later. Economically speaking, Bitcoin futures between SegWit and SegWit2X showed strong economic dominance in favor of SegWit (SegWit2X futures were traded at a fraction in value of SegWit futures: I personally made a tidy but small amount of money betting against SegWit2X in the futures market), so suggesting that NYA achieved 80% dominance even in mining is laughable, but the NYA text that ties bit 4 to SegWit2X still exists.
Historically, BIP91 triggered which caused SegWit to activate before the BIP148 shorter timeout. BIP148 proponents continue to hold this day that it was the BIP148 shorter timeout and no-compromises-activate-on-August-1 that made miners flock to BIP91 as a face-saving tactic that actually removed the second clause of NYA. NYA supporters keep pointing to the bit 4 text in the NYA and the historical activation of BIP91 as a failed promise by Bitcoin developers.

Taproot Activation Proposals

There are two primary proposals I can see for Taproot activation:
  1. BIP8.
  2. Modern Softfork Activation.
We have discussed BIP8: roughly, it has bit and timeout, if 95% of miners signal bit it activates, at the end of timeout it activates. (EDIT: BIP8 has had recent updates: at the end of timeout it can now activate or fail. For the most part, in the below text "BIP8", means BIP8-and-activate-at-timeout, and "BIP9" means BIP8-and-fail-at-timeout)
So let's take a look at Modern Softfork Activation!

Modern Softfork Activation

This is a more complex activation method, composed of BIP9 and BIP8 as supcomponents.
  1. First have a 12-month BIP9 (fail at timeout).
  2. If the above fails to activate, have a 6-month discussion period during which users and developers and miners discuss whether to continue to step 3.
  3. Have a 24-month BIP8 (activate at timeout).
The total above is 42 months, if you are counting: 3.5 years worst-case activation.
The logic here is that if there are no problems, BIP9 will work just fine anyway. And if there are problems, the 6-month period should weed it out. Finally, miners cannot hold the feature hostage since the 24-month BIP8 period will exist anyway.

PSA: Being Resilient to Upgrades

Software is very birttle.
Anyone who has been using software for a long time has experienced something like this:
  1. You hear a new version of your favorite software has a nice new feature.
  2. Excited, you install the new version.
  3. You find that the new version has subtle incompatibilities with your current workflow.
  4. You are sad and downgrade to the older version.
  5. You find out that the new version has changed your files in incompatible ways that the old version cannot work with anymore.
  6. You tearfully reinstall the newer version and figure out how to get your lost productivity now that you have to adapt to a new workflow
If you are a technically-competent user, you might codify your workflow into a bunch of programs. And then you upgrade one of the external pieces of software you are using, and find that it has a subtle incompatibility with your current workflow which is based on a bunch of simple programs you wrote yourself. And if those simple programs are used as the basis of some important production system, you hve just screwed up because you upgraded software on an important production system.
And well, one of the issues with new softfork activation is that if not enough people (users and miners) upgrade to the newest Bitcoin software, the security of the new softfork rules are at risk.
Upgrading software of any kind is always a risk, and the more software you build on top of the software-being-upgraded, the greater you risk your tower of software collapsing while you change its foundations.
So if you have some complex Bitcoin-manipulating system with Bitcoin somewhere at the foundations, consider running two Bitcoin nodes:
  1. One is a "stable-version" Bitcoin node. Once it has synced, set it up to connect=x.x.x.x to the second node below (so that your ISP bandwidth is only spent on the second node). Use this node to run all your software: it's a stable version that you don't change for long periods of time. Enable txiindex, disable pruning, whatever your software needs.
  2. The other is an "always-up-to-date" Bitcoin Node. Keep its stoarge down with pruning (initially sync it off the "stable-version" node). You can't use blocksonly if your "stable-version" node needs to send transactions, but otherwise this "always-up-to-date" Bitcoin node can be kept as a low-resource node, so you can run both nodes in the same machine.
When a new Bitcoin version comes up, you just upgrade the "always-up-to-date" Bitcoin node. This protects you if a future softfork activates, you will only receive valid Bitcoin blocks and transactions. Since this node has nothing running on top of it, it is just a special peer of the "stable-version" node, any software incompatibilities with your system software do not exist.
Your "stable-version" Bitcoin node remains the same version until you are ready to actually upgrade this node and are prepared to rewrite most of the software you have running on top of it due to version compatibility problems.
When upgrading the "always-up-to-date", you can bring it down safely and then start it later. Your "stable-version" wil keep running, disconnected from the network, but otherwise still available for whatever queries. You do need some system to stop the "always-up-to-date" node if for any reason the "stable-version" goes down (otherwisee if the "always-up-to-date" advances its pruning window past what your "stable-version" has, the "stable-version" cannot sync afterwards), but if you are technically competent enough that you need to do this, you are technically competent enough to write such a trivial monitor program (EDIT: gmax notes you can adjust the pruning window by RPC commands to help with this as well).
This recommendation is from gmaxwell on IRC, by the way.
submitted by almkglor to Bitcoin [link] [comments]

Since they're calling for r/btc to be banned...

Maybe it's time to discuss bitcoin's history again. Credit to u/singularity87 for the original post over 3 years ago.

People should get the full story of bitcoin because it is probably one of the strangest of all reddit subs.
bitcoin, the main sub for the bitcoin community is held and run by a person who goes by the pseudonym u/theymos. Theymos not only controls bitcoin, but also and These are top three communication channels for the bitcoin community, all controlled by just one person.
For most of bitcoin's history this did not create a problem (at least not an obvious one anyway) until around mid 2015. This happened to be around the time a new player appeared on the scene, a for-profit company called Blockstream. Blockstream was made up of/hired many (but not all) of the main bitcoin developers. (To be clear, Blockstream was founded before mid 2015 but did not become publicly active until then). A lot of people, including myself, tried to point out there we're some very serious potential conflicts of interest that could arise when one single company controls most of the main developers for the biggest decentralised and distributed cryptocurrency. There were a lot of unknowns but people seemed to give them the benefit of the doubt because they were apparently about to release some new software called "sidechains" that could offer some benefits to the network.
Not long after Blockstream came on the scene the issue of bitcoin's scalability once again came to forefront of the community. This issue came within the community a number of times since bitcoins inception. Bitcoin, as dictated in the code, cannot handle any more than around 3 transactions per second at the moment. To put that in perspective Paypal handles around 15 transactions per second on average and VISA handles something like 2000 transactions per second. The discussion in the community has been around how best to allow bitcoin to scale to allow a higher number of transactions in a given amount of time. I suggest that if anyone is interested in learning more about this problem from a technical angle, they go to btc and do a search. It's a complex issue but for many who have followed bitcoin for many years, the possible solutions seem relatively obvious. Essentially, currently the limit is put in place in just a few lines of code. This was not originally present when bitcoin was first released. It was in fact put in place afterwards as a measure to stop a bloating attack on the network. Because all bitcoin transactions have to be stored forever on the bitcoin network, someone could theoretically simply transmit a large number of transactions which would have to be stored by the entire network forever. When bitcoin was released, transactions were actually for free as the only people running the network were enthusiasts. In fact a single bitcoin did not even have any specific value so it would be impossible set a fee value. This meant that a malicious person could make the size of the bitcoin ledger grow very rapidly without much/any cost which would stop people from wanting to join the network due to the resource requirements needed to store it, which at the time would have been for very little gain.
Towards the end of the summer last year, this bitcoin scaling debate surfaced again as it was becoming clear that the transaction limit for bitcoin was semi regularly being reached and that it would not be long until it would be regularly hit and the network would become congested. This was a very serious issue for a currency. Bitcoin had made progress over the years to the point of retailers starting to offer it as a payment option. Bitcoin companies like, Microsoft, Paypal, Steam and many more had began to adopt it. If the transaction limit would be constantly maxed out, the network would become unreliable and slow for users. Users and businesses would not be able to make a reliable estimate when their transaction would be confirmed by the network.
Users, developers and businesses (which at the time was pretty much the only real bitcoin subreddit) started to discuss how we should solve the problem bitcoin. There was significant support from the users and businesses behind a simple solution put forward by the developer Gavin Andreesen. Gavin was the lead developer after Satoshi Nakamoto left bitcoin and he left it in his hands. Gavin initially proposed a very simple solution of increasing the limit which was to change the few lines of code to increase the maximum number of transactions that are allowed. For most of bitcoin's history the transaction limit had been set far far higher than the number of transactions that could potentially happen on the network. The concept of increasing the limit one time was based on the fact that history had proven that no issue had been cause by this in the past.
A certain group of bitcoin developers decided that increasing the limit by this amount was too much and that it was dangerous. They said that the increased use of resources that the network would use would create centralisation pressures which could destroy the network. The theory was that a miner of the network with more resources could publish many more transactions than a competing small miner could handle and therefore the network would tend towards few large miners rather than many small miners. The group of developers who supported this theory were all developers who worked for the company Blockstream. The argument from people in support of increasing the transaction capacity by this amount was that there are always inherent centralisation pressure with bitcoin mining. For example miners who can access the cheapest electricity will tend to succeed and that bigger miners will be able to find this cheaper electricity easier. Miners who have access to the most efficient computer chips will tend to succeed and that larger miners are more likely to be able to afford the development of them. The argument from Gavin and other who supported increasing the transaction capacity by this method are essentially there are economies of scale in mining and that these economies have far bigger centralisation pressures than increased resource cost for a larger number of transactions (up to the new limit proposed). For example, at the time the total size of the blockchain was around 50GB. Even for the cost of a 500GB SSD is only $150 and would last a number of years. This is in-comparison to the $100,000's in revenue per day a miner would be making.
Various developers put forth various other proposals, including Gavin Andresen who put forth a more conservative increase that would then continue to increase over time inline with technological improvements. Some of the employees of blockstream also put forth some proposals, but all were so conservative, it would take bitcoin many decades before it could reach a scale of VISA. Even though there was significant support from the community behind Gavin's simple proposal of increasing the limit it was becoming clear certain members of the bitcoin community who were part of Blockstream were starting to become increasingly vitriolic and divisive. Gavin then teamed up with one of the other main bitcoin developers Mike Hearn and released a coded (i.e. working) version of the bitcoin software that would only activate if it was supported by a significant majority of the network. What happened next was where things really started to get weird.
After this free and open source software was released, Theymos, the person who controls all the main communication channels for the bitcoin community implemented a new moderation policy that disallowed any discussion of this new software. Specifically, if people were to discuss this software, their comments would be deleted and ultimately they would be banned temporarily or permanently. This caused chaos within the community as there was very clear support for this software at the time and it seemed our best hope for