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Gridcoin 5.0.0.0-Mandatory "Fern" Release

https://github.com/gridcoin-community/Gridcoin-Research/releases/tag/5.0.0.0
Finally! After over ten months of development and testing, "Fern" has arrived! This is a whopper. 240 pull requests merged. Essentially a complete rewrite that was started with the scraper (the "neural net" rewrite) in "Denise" has now been completed. Practically the ENTIRE Gridcoin specific codebase resting on top of the vanilla Bitcoin/Peercoin/Blackcoin vanilla PoS code has been rewritten. This removes the team requirement at last (see below), although there are many other important improvements besides that.
Fern was a monumental undertaking. We had to encode all of the old rules active for the v10 block protocol in new code and ensure that the new code was 100% compatible. This had to be done in such a way as to clear out all of the old spaghetti and ring-fence it with tightly controlled class implementations. We then wrote an entirely new, simplified ruleset for research rewards and reengineered contracts (which includes beacon management, polls, and voting) using properly classed code. The fundamentals of Gridcoin with this release are now on a very sound and maintainable footing, and the developers believe the codebase as updated here will serve as the fundamental basis for Gridcoin's future roadmap.
We have been testing this for MONTHS on testnet in various stages. The v10 (legacy) compatibility code has been running on testnet continuously as it was developed to ensure compatibility with existing nodes. During the last few months, we have done two private testnet forks and then the full public testnet testing for v11 code (the new protocol which is what Fern implements). The developers have also been running non-staking "sentinel" nodes on mainnet with this code to verify that the consensus rules are problem-free for the legacy compatibility code on the broader mainnet. We believe this amount of testing is going to result in a smooth rollout.
Given the amount of changes in Fern, I am presenting TWO changelogs below. One is high level, which summarizes the most significant changes in the protocol. The second changelog is the detailed one in the usual format, and gives you an inkling of the size of this release.

Highlights

Protocol

Note that the protocol changes will not become active until we cross the hard-fork transition height to v11, which has been set at 2053000. Given current average block spacing, this should happen around October 4, about one month from now.
Note that to get all of the beacons in the network on the new protocol, we are requiring ALL beacons to be validated. A two week (14 day) grace period is provided by the code, starting at the time of the transition height, for people currently holding a beacon to validate the beacon and prevent it from expiring. That means that EVERY CRUNCHER must advertise and validate their beacon AFTER the v11 transition (around Oct 4th) and BEFORE October 18th (or more precisely, 14 days from the actual date of the v11 transition). If you do not advertise and validate your beacon by this time, your beacon will expire and you will stop earning research rewards until you advertise and validate a new beacon. This process has been made much easier by a brand new beacon "wizard" that helps manage beacon advertisements and renewals. Once a beacon has been validated and is a v11 protocol beacon, the normal 180 day expiration rules apply. Note, however, that the 180 day expiration on research rewards has been removed with the Fern update. This means that while your beacon might expire after 180 days, your earned research rewards will be retained and can be claimed by advertising a beacon with the same CPID and going through the validation process again. In other words, you do not lose any earned research rewards if you do not stake a block within 180 days and keep your beacon up-to-date.
The transition height is also when the team requirement will be relaxed for the network.

GUI

Besides the beacon wizard, there are a number of improvements to the GUI, including new UI transaction types (and icons) for staking the superblock, sidestake sends, beacon advertisement, voting, poll creation, and transactions with a message. The main screen has been revamped with a better summary section, and better status icons. Several changes under the hood have improved GUI performance. And finally, the diagnostics have been revamped.

Blockchain

The wallet sync speed has been DRASTICALLY improved. A decent machine with a good network connection should be able to sync the entire mainnet blockchain in less than 4 hours. A fast machine with a really fast network connection and a good SSD can do it in about 2.5 hours. One of our goals was to reduce or eliminate the reliance on snapshots for mainnet, and I think we have accomplished that goal with the new sync speed. We have also streamlined the in-memory structures for the blockchain which shaves some memory use.
There are so many goodies here it is hard to summarize them all.
I would like to thank all of the contributors to this release, but especially thank @cyrossignol, whose incredible contributions formed the backbone of this release. I would also like to pay special thanks to @barton2526, @caraka, and @Quezacoatl1, who tirelessly helped during the testing and polishing phase on testnet with testing and repeated builds for all architectures.
The developers are proud to present this release to the community and we believe this represents the starting point for a true renaissance for Gridcoin!

Summary Changelog

Accrual

Changed

Most significantly, nodes calculate research rewards directly from the magnitudes in EACH superblock between stakes instead of using a two- or three- point average based on a CPID's current magnitude and the magnitude for the CPID when it last staked. For those long-timers in the community, this has been referred to as "Superblock Windows," and was first done in proof-of-concept form by @denravonska.

Removed

Beacons

Added

Changed

Removed

Unaltered

As a reminder:

Superblocks

Added

Changed

Removed

Voting

Added

Changed

Removed

Detailed Changelog

[5.0.0.0] 2020-09-03, mandatory, "Fern"

Added

Changed

Removed

Fixed

submitted by jamescowens to gridcoin [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]

A new whitepaper analysing the performance and scalability of the Streamr pub/sub messaging Network is now available. Take a look at some of the fascinating key results in this introductory blog

A new whitepaper analysing the performance and scalability of the Streamr pub/sub messaging Network is now available. Take a look at some of the fascinating key results in this introductory blog

Streamr Network: Performance and Scalability Whitepaper


https://preview.redd.it/bstqyn43x4j51.png?width=2600&format=png&auto=webp&s=81683ca6303ab84ab898c096345464111d674ee5
The Corea milestone of the Streamr Network went live in late 2019. Since then a few people in the team have been working on an academic whitepaper to describe its design principles, position it with respect to prior art, and prove certain properties it has. The paper is now ready, and it has been submitted to the IEEE Access journal for peer review. It is also now published on the new Papers section on the project website. In this blog, I’ll introduce the paper and explain its key results. All the figures presented in this post are from the paper.
The reasons for doing this research and writing this paper were simple: many prospective users of the Network, especially more serious ones such as enterprises, ask questions like ‘how does it scale?’, ‘why does it scale?’, ‘what is the latency in the network?’, and ‘how much bandwidth is consumed?’. While some answers could be provided before, the Network in its currently deployed form is still small-scale and can’t really show a track record of scalability for example, so there was clearly a need to produce some in-depth material about the structure of the Network and its performance at large, global scale. The paper answers these questions.
Another reason is that decentralized peer-to-peer networks have experienced a new renaissance due to the rise in blockchain networks. Peer-to-peer pub/sub networks were a hot research topic in the early 2000s, but not many real-world implementations were ever created. Today, most blockchain networks use methods from that era under the hood to disseminate block headers, transactions, and other events important for them to function. Other megatrends like IoT and social media are also creating demand for new kinds of scalable message transport layers.

The latency vs. bandwidth tradeoff

The current Streamr Network uses regular random graphs as stream topologies. ‘Regular’ here means that nodes connect to a fixed number of other nodes that publish or subscribe to the same stream, and ‘random’ means that those nodes are selected randomly.
Random connections can of course mean that absurd routes get formed occasionally, for example a data point might travel from Germany to France via the US. But random graphs have been studied extensively in the academic literature, and their properties are not nearly as bad as the above example sounds — such graphs are actually quite good! Data always takes multiple routes in the network, and only the fastest route counts. The less-than-optimal routes are there for redundancy, and redundancy is good, because it improves security and churn tolerance.
There is an important parameter called node degree, which is the fixed number of nodes to which each node in a topology connects. A higher node degree means more duplication and thus more bandwidth consumption for each node, but it also means that fast routes are more likely to form. It’s a tradeoff; better latency can be traded for worse bandwidth consumption. In the following section, we’ll go deeper into analyzing this relationship.

Network diameter scales logarithmically

One useful metric to estimate the behavior of latency is the network diameter, which is the number of hops on the shortest path between the most distant pair of nodes in the network (i.e. the “longest shortest path”. The below plot shows how the network diameter behaves depending on node degree and number of nodes.

Network diameter
We can see that the network diameter increases logarithmically (very slowly), and a higher node degree ‘flattens the curve’. This is a property of random regular graphs, and this is very good — growing from 10,000 nodes to 100,000 nodes only increases the diameter by a few hops! To analyse the effect of the node degree further, we can plot the maximum network diameter using various node degrees:
Network diameter in network of 100 000 nodes
We can see that there are diminishing returns for increasing the node degree. On the other hand, the penalty (number of duplicates, i.e. bandwidth consumption), increases linearly with node degree:

Number of duplicates received by the non-publisher nodes
In the Streamr Network, each stream forms its own separate overlay network and can even have a custom node degree. This allows the owner of the stream to configure their preferred latency/bandwidth balance (imagine such a slider control in the Streamr Core UI). However, finding a good default value is important. From this analysis, we can conclude that:
  • The logarithmic behavior of network diameter leads us to hope that latency might behave logarithmically too, but since the number of hops is not the same as latency (in milliseconds), the scalability needs to be confirmed in the real world (see next section).
  • A node degree of 4 yields good latency/bandwidth balance, and we have selected this as the default value in the Streamr Network. This value is also used in all the real-world experiments described in the next section.
It’s worth noting that in such a network, the bandwidth requirement for publishers is determined by the node degree and not the number of subscribers. With a node degree 4 and a million subscribers, the publisher only uploads 4 copies of a data point, and the million subscribing nodes share the work of distributing the message among themselves. In contrast, a centralized data broker would need to push out a million copies.

Latency scales logarithmically

To see if actual latency scales logarithmically in real-world conditions, we ran large numbers of nodes in 16 different Amazon AWS data centers around the world. We ran experiments with network sizes between 32 to 2048 nodes. Each node published messages to the network, and we measured how long it took for the other nodes to get the message. The experiment was repeated 10 times for each network size.
The below image displays one of the key results of the paper. It shows a CDF (cumulative distribution function) of the measured latencies across all experiments. The y-axis runs from 0 to 1, i.e. 0% to 100%.
CDF of message propagation delay
From this graph we can easily read things like: in a 32 nodes network (blue line), 50% of message deliveries happened within 150 ms globally, and all messages were delivered in around 250 ms. In the largest network of 2048 nodes (pink line), 99% of deliveries happened within 362 ms globally.
To put these results in context, PubNub, a centralized message brokering service, promises to deliver messages within 250 ms — and that’s a centralized service! Decentralization comes with unquestionable benefits (no vendor lock-in, no trust required, network effects, etc.), but if such protocols are inferior in terms of performance or cost, they won’t get adopted. It’s pretty safe to say that the Streamr Network is on par with centralized services even when it comes to latency, which is usually the Achilles’ heel of P2P networks (think of how slow blockchains are!). And the Network will only get better with time.
Then we tackled the big question: does the latency behave logarithmically?
Mean message propagation delay in Amazon experiments
Above, the thick line is the average latency for each network size. From the graph, we can see that the latency grows logarithmically as the network size increases, which means excellent scalability.
The shaded area shows the difference between the best and worst average latencies in each repeat. Here we can see the element of chance at play; due to the randomness in which nodes become neighbours, some topologies are faster than others. Given enough repeats, some near-optimal topologies can be found. The difference between average topologies and the best topologies gives us a glimpse of how much room for optimisation there is, i.e. with a smarter-than-random topology construction, how much improvement is possible (while still staying in the realm of regular graphs)? Out of the observed topologies, the difference between the average and the best observed topology is between 5–13%, so not that much. Other subclasses of graphs, such as irregular graphs, trees, and so on, can of course unlock more room for improvement, but they are different beasts and come with their own disadvantages too.
It’s also worth asking: how much worse is the measured latency compared to the fastest possible latency, i.e. that of a direct connection? While having direct connections between a publisher and subscribers is definitely not scalable, secure, or often even feasible due to firewalls, NATs and such, it’s still worth asking what the latency penalty of peer-to-peer is.

Relative delay penalty in Amazon experiments
As you can see, this plot has the same shape as the previous one, but the y-axis is different. Here, we are showing the relative delay penalty (RDP). It’s the latency in the peer-to-peer network (shown in the previous plot), divided by the latency of a direct connection measured with the ping tool. So a direct connection equals an RDP value of 1, and the measured RDP in the peer-to-peer network is roughly between 2 and 3 in the observed topologies. It increases logarithmically with network size, just like absolute latency.
Again, given that latency is the Achilles’ heel of decentralized systems, that’s not bad at all. It shows that such a network delivers acceptable performance for the vast majority of use cases, only excluding the most latency-sensitive ones, such as online gaming or arbitrage trading. For most other use cases, it doesn’t matter whether it takes 25 or 75 milliseconds to deliver a data point.

Latency is predictable

It’s useful for a messaging system to have consistent and predictable latency. Imagine for example a smart traffic system, where cars can alert each other about dangers on the road. It would be pretty bad if, even minutes after publishing it, some cars still haven’t received the warning. However, such delays easily occur in peer-to-peer networks. Everyone in the crypto space has seen first-hand how plenty of Bitcoin or Ethereum nodes lag even minutes behind the latest chain state.
So we wanted to see whether it would be possible to estimate the latencies in the peer-to-peer network if the topology and the latencies between connected pairs of nodes are known. We applied Dijkstra’s algorithm to compute estimates for average latencies from the input topology data, and compared the estimates to the actual measured average latencies:
Mean message propagation delay in Amazon experiments
We can see that, at least in these experiments, the estimates seemed to provide a lower bound for the actual values, and the average estimation error was 3.5%. The measured value is higher than the estimated one because the estimation only considers network delays, while in reality there is also a little bit of a processing delay at each node.

Conclusion

The research has shown that the Streamr Network can be expected to deliver messages in roughly 150–350 milliseconds worldwide, even at a large scale with thousands of nodes subscribing to a stream. This is on par with centralized message brokers today, showing that the decentralized and peer-to-peer approach is a viable alternative for all but the most latency-sensitive applications.
It’s thrilling to think that by accepting a latency only 2–3 times longer than the latency of an unscalable and insecure direct connecion, applications can interconnect over an open fabric with global scalability, no single point of failure, no vendor lock-in, and no need to trust anyone — all that becomes available out of the box.
In the real-time data space, there are plenty of other aspects to explore, which we didn’t cover in this paper. For example, we did not measure throughput characteristics of network topologies. Different streams are independent, so clearly there’s scalability in the number of streams, and heavy streams can be partitioned, allowing each stream to scale too. Throughput is mainly limited, therefore, by the hardware and network connection used by the network nodes involved in a topology. Measuring the maximum throughput would basically be measuring the hardware as well as the performance of our implemented code. While interesting, this is not a high priority research target at this point in time. And thanks to the redundancy in the network, individual slow nodes do not slow down the whole topology; the data will arrive via faster nodes instead.
Also out of scope for this paper is analysing the costs of running such a network, including the OPEX for publishers and node operators. This is a topic of ongoing research, which we’re currently doing as part of designing the token incentive mechanisms of the Streamr Network, due to be implemented in a later milestone.
I hope that this blog has provided some insight into the fascinating results the team uncovered during this research. For a more in-depth look at the context of this work, and more detail about the research, we invite you to read the full paper.
If you have an interest in network performance and scalability from a developer or enterprise perspective, we will be hosting a talk about this research in the coming weeks, so keep an eye out for more details on the Streamr social media channels. In the meantime, feedback and comments are welcome. Please add a comment to this Reddit thread or email [[email protected]](mailto:[email protected]).
Originally published by. Henri at blog.streamr.network on August 24, 2020.
submitted by thamilton5 to streamr [link] [comments]

Litecoin MimbleWimble July Update.

With the crypto markets finally breaking out above the 3 year downtrend, confidence is returning to the space and to cryptocurrency as a technology. With that said, we have also taken another leap towards the launch of MimbleWimble on the Litecoin Network, so let’s jump into what’s new and without further ado let David Burkett, the projects lead developer share his progress: The focus this month was on the Initial Block Download. Before I can detail the progress made, I need to give some background info for those not intimately familiar with mimblewimble. The biggest innovation behind mimblewimble is that, in order to verify the chain, you just need to know all of the unspent coins/outputs, and a small part of each transaction called the “Kernel.” These 2 things together are called the “chain state.” In bitcoin/litecoin, each block header uses a merkle tree to commit to only the transactions in that block. Since we don’t want to require everyone to download all old mimblewimble blocks, or to know about all old, spent outputs, we use a different structure to commit to the transactions. Each mimblewimble header commits to the root of 2 different Merkle Mountain Ranges(MMRs). One represents all historical kernels up to that block, and the other represents all historical outputs/coins. Merkle Mountain Ranges are a different sort of tree that supports “pruning”, which means we can verify the root of the structure without knowing all of its members (called leaves). For an in-depth look at how this works, I recommend reading
submitted by Jefferywachmanq to litecoin [link] [comments]

Bitcoin (BTC)A Peer-to-Peer Electronic Cash System.

Bitcoin (BTC)A Peer-to-Peer Electronic Cash System.
  • Bitcoin (BTC) is a peer-to-peer cryptocurrency that aims to function as a means of exchange that is independent of any central authority. BTC can be transferred electronically in a secure, verifiable, and immutable way.
  • Launched in 2009, BTC is the first virtual currency to solve the double-spending issue by timestamping transactions before broadcasting them to all of the nodes in the Bitcoin network. The Bitcoin Protocol offered a solution to the Byzantine Generals’ Problem with a blockchain network structure, a notion first created by Stuart Haber and W. Scott Stornetta in 1991.
  • Bitcoin’s whitepaper was published pseudonymously in 2008 by an individual, or a group, with the pseudonym “Satoshi Nakamoto”, whose underlying identity has still not been verified.
  • The Bitcoin protocol uses an SHA-256d-based Proof-of-Work (PoW) algorithm to reach network consensus. Its network has a target block time of 10 minutes and a maximum supply of 21 million tokens, with a decaying token emission rate. To prevent fluctuation of the block time, the network’s block difficulty is re-adjusted through an algorithm based on the past 2016 block times.
  • With a block size limit capped at 1 megabyte, the Bitcoin Protocol has supported both the Lightning Network, a second-layer infrastructure for payment channels, and Segregated Witness, a soft-fork to increase the number of transactions on a block, as solutions to network scalability.

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1. What is Bitcoin (BTC)?

  • Bitcoin is a peer-to-peer cryptocurrency that aims to function as a means of exchange and is independent of any central authority. Bitcoins are transferred electronically in a secure, verifiable, and immutable way.
  • Network validators, whom are often referred to as miners, participate in the SHA-256d-based Proof-of-Work consensus mechanism to determine the next global state of the blockchain.
  • The Bitcoin protocol has a target block time of 10 minutes, and a maximum supply of 21 million tokens. The only way new bitcoins can be produced is when a block producer generates a new valid block.
  • The protocol has a token emission rate that halves every 210,000 blocks, or approximately every 4 years.
  • Unlike public blockchain infrastructures supporting the development of decentralized applications (Ethereum), the Bitcoin protocol is primarily used only for payments, and has only very limited support for smart contract-like functionalities (Bitcoin “Script” is mostly used to create certain conditions before bitcoins are used to be spent).

2. Bitcoin’s core features

For a more beginner’s introduction to Bitcoin, please visit Binance Academy’s guide to Bitcoin.

Unspent Transaction Output (UTXO) model

A UTXO transaction works like cash payment between two parties: Alice gives money to Bob and receives change (i.e., unspent amount). In comparison, blockchains like Ethereum rely on the account model.
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Nakamoto consensus

In the Bitcoin network, anyone can join the network and become a bookkeeping service provider i.e., a validator. All validators are allowed in the race to become the block producer for the next block, yet only the first to complete a computationally heavy task will win. This feature is called Proof of Work (PoW).
The probability of any single validator to finish the task first is equal to the percentage of the total network computation power, or hash power, the validator has. For instance, a validator with 5% of the total network computation power will have a 5% chance of completing the task first, and therefore becoming the next block producer.
Since anyone can join the race, competition is prone to increase. In the early days, Bitcoin mining was mostly done by personal computer CPUs.
As of today, Bitcoin validators, or miners, have opted for dedicated and more powerful devices such as machines based on Application-Specific Integrated Circuit (“ASIC”).
Proof of Work secures the network as block producers must have spent resources external to the network (i.e., money to pay electricity), and can provide proof to other participants that they did so.
With various miners competing for block rewards, it becomes difficult for one single malicious party to gain network majority (defined as more than 51% of the network’s hash power in the Nakamoto consensus mechanism). The ability to rearrange transactions via 51% attacks indicates another feature of the Nakamoto consensus: the finality of transactions is only probabilistic.
Once a block is produced, it is then propagated by the block producer to all other validators to check on the validity of all transactions in that block. The block producer will receive rewards in the network’s native currency (i.e., bitcoin) as all validators approve the block and update their ledgers.

The blockchain

Block production

The Bitcoin protocol utilizes the Merkle tree data structure in order to organize hashes of numerous individual transactions into each block. This concept is named after Ralph Merkle, who patented it in 1979.
With the use of a Merkle tree, though each block might contain thousands of transactions, it will have the ability to combine all of their hashes and condense them into one, allowing efficient and secure verification of this group of transactions. This single hash called is a Merkle root, which is stored in the Block Header of a block. The Block Header also stores other meta information of a block, such as a hash of the previous Block Header, which enables blocks to be associated in a chain-like structure (hence the name “blockchain”).
An illustration of block production in the Bitcoin Protocol is demonstrated below.

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Block time and mining difficulty

Block time is the period required to create the next block in a network. As mentioned above, the node who solves the computationally intensive task will be allowed to produce the next block. Therefore, block time is directly correlated to the amount of time it takes for a node to find a solution to the task. The Bitcoin protocol sets a target block time of 10 minutes, and attempts to achieve this by introducing a variable named mining difficulty.
Mining difficulty refers to how difficult it is for the node to solve the computationally intensive task. If the network sets a high difficulty for the task, while miners have low computational power, which is often referred to as “hashrate”, it would statistically take longer for the nodes to get an answer for the task. If the difficulty is low, but miners have rather strong computational power, statistically, some nodes will be able to solve the task quickly.
Therefore, the 10 minute target block time is achieved by constantly and automatically adjusting the mining difficulty according to how much computational power there is amongst the nodes. The average block time of the network is evaluated after a certain number of blocks, and if it is greater than the expected block time, the difficulty level will decrease; if it is less than the expected block time, the difficulty level will increase.

What are orphan blocks?

In a PoW blockchain network, if the block time is too low, it would increase the likelihood of nodes producingorphan blocks, for which they would receive no reward. Orphan blocks are produced by nodes who solved the task but did not broadcast their results to the whole network the quickest due to network latency.
It takes time for a message to travel through a network, and it is entirely possible for 2 nodes to complete the task and start to broadcast their results to the network at roughly the same time, while one’s messages are received by all other nodes earlier as the node has low latency.
Imagine there is a network latency of 1 minute and a target block time of 2 minutes. A node could solve the task in around 1 minute but his message would take 1 minute to reach the rest of the nodes that are still working on the solution. While his message travels through the network, all the work done by all other nodes during that 1 minute, even if these nodes also complete the task, would go to waste. In this case, 50% of the computational power contributed to the network is wasted.
The percentage of wasted computational power would proportionally decrease if the mining difficulty were higher, as it would statistically take longer for miners to complete the task. In other words, if the mining difficulty, and therefore targeted block time is low, miners with powerful and often centralized mining facilities would get a higher chance of becoming the block producer, while the participation of weaker miners would become in vain. This introduces possible centralization and weakens the overall security of the network.
However, given a limited amount of transactions that can be stored in a block, making the block time too longwould decrease the number of transactions the network can process per second, negatively affecting network scalability.

3. Bitcoin’s additional features

Segregated Witness (SegWit)

Segregated Witness, often abbreviated as SegWit, is a protocol upgrade proposal that went live in August 2017.
SegWit separates witness signatures from transaction-related data. Witness signatures in legacy Bitcoin blocks often take more than 50% of the block size. By removing witness signatures from the transaction block, this protocol upgrade effectively increases the number of transactions that can be stored in a single block, enabling the network to handle more transactions per second. As a result, SegWit increases the scalability of Nakamoto consensus-based blockchain networks like Bitcoin and Litecoin.
SegWit also makes transactions cheaper. Since transaction fees are derived from how much data is being processed by the block producer, the more transactions that can be stored in a 1MB block, the cheaper individual transactions become.
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The legacy Bitcoin block has a block size limit of 1 megabyte, and any change on the block size would require a network hard-fork. On August 1st 2017, the first hard-fork occurred, leading to the creation of Bitcoin Cash (“BCH”), which introduced an 8 megabyte block size limit.
Conversely, Segregated Witness was a soft-fork: it never changed the transaction block size limit of the network. Instead, it added an extended block with an upper limit of 3 megabytes, which contains solely witness signatures, to the 1 megabyte block that contains only transaction data. This new block type can be processed even by nodes that have not completed the SegWit protocol upgrade.
Furthermore, the separation of witness signatures from transaction data solves the malleability issue with the original Bitcoin protocol. Without Segregated Witness, these signatures could be altered before the block is validated by miners. Indeed, alterations can be done in such a way that if the system does a mathematical check, the signature would still be valid. However, since the values in the signature are changed, the two signatures would create vastly different hash values.
For instance, if a witness signature states “6,” it has a mathematical value of 6, and would create a hash value of 12345. However, if the witness signature were changed to “06”, it would maintain a mathematical value of 6 while creating a (faulty) hash value of 67890.
Since the mathematical values are the same, the altered signature remains a valid signature. This would create a bookkeeping issue, as transactions in Nakamoto consensus-based blockchain networks are documented with these hash values, or transaction IDs. Effectively, one can alter a transaction ID to a new one, and the new ID can still be valid.
This can create many issues, as illustrated in the below example:
  1. Alice sends Bob 1 BTC, and Bob sends Merchant Carol this 1 BTC for some goods.
  2. Bob sends Carols this 1 BTC, while the transaction from Alice to Bob is not yet validated. Carol sees this incoming transaction of 1 BTC to him, and immediately ships goods to B.
  3. At the moment, the transaction from Alice to Bob is still not confirmed by the network, and Bob can change the witness signature, therefore changing this transaction ID from 12345 to 67890.
  4. Now Carol will not receive his 1 BTC, as the network looks for transaction 12345 to ensure that Bob’s wallet balance is valid.
  5. As this particular transaction ID changed from 12345 to 67890, the transaction from Bob to Carol will fail, and Bob will get his goods while still holding his BTC.
With the Segregated Witness upgrade, such instances can not happen again. This is because the witness signatures are moved outside of the transaction block into an extended block, and altering the witness signature won’t affect the transaction ID.
Since the transaction malleability issue is fixed, Segregated Witness also enables the proper functioning of second-layer scalability solutions on the Bitcoin protocol, such as the Lightning Network.

Lightning Network

Lightning Network is a second-layer micropayment solution for scalability.
Specifically, Lightning Network aims to enable near-instant and low-cost payments between merchants and customers that wish to use bitcoins.
Lightning Network was conceptualized in a whitepaper by Joseph Poon and Thaddeus Dryja in 2015. Since then, it has been implemented by multiple companies. The most prominent of them include Blockstream, Lightning Labs, and ACINQ.
A list of curated resources relevant to Lightning Network can be found here.
In the Lightning Network, if a customer wishes to transact with a merchant, both of them need to open a payment channel, which operates off the Bitcoin blockchain (i.e., off-chain vs. on-chain). None of the transaction details from this payment channel are recorded on the blockchain, and only when the channel is closed will the end result of both party’s wallet balances be updated to the blockchain. The blockchain only serves as a settlement layer for Lightning transactions.
Since all transactions done via the payment channel are conducted independently of the Nakamoto consensus, both parties involved in transactions do not need to wait for network confirmation on transactions. Instead, transacting parties would pay transaction fees to Bitcoin miners only when they decide to close the channel.
https://preview.redd.it/cy56icarf3151.png?width=1601&format=png&auto=webp&s=b239a63c6a87ec6cc1b18ce2cbd0355f8831c3a8
One limitation to the Lightning Network is that it requires a person to be online to receive transactions attributing towards him. Another limitation in user experience could be that one needs to lock up some funds every time he wishes to open a payment channel, and is only able to use that fund within the channel.
However, this does not mean he needs to create new channels every time he wishes to transact with a different person on the Lightning Network. If Alice wants to send money to Carol, but they do not have a payment channel open, they can ask Bob, who has payment channels open to both Alice and Carol, to help make that transaction. Alice will be able to send funds to Bob, and Bob to Carol. Hence, the number of “payment hubs” (i.e., Bob in the previous example) correlates with both the convenience and the usability of the Lightning Network for real-world applications.

Schnorr Signature upgrade proposal

Elliptic Curve Digital Signature Algorithm (“ECDSA”) signatures are used to sign transactions on the Bitcoin blockchain.
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However, many developers now advocate for replacing ECDSA with Schnorr Signature. Once Schnorr Signatures are implemented, multiple parties can collaborate in producing a signature that is valid for the sum of their public keys.
This would primarily be beneficial for network scalability. When multiple addresses were to conduct transactions to a single address, each transaction would require their own signature. With Schnorr Signature, all these signatures would be combined into one. As a result, the network would be able to store more transactions in a single block.
https://preview.redd.it/axg3wayag3151.png?width=1601&format=png&auto=webp&s=93d958fa6b0e623caa82ca71fe457b4daa88c71e
The reduced size in signatures implies a reduced cost on transaction fees. The group of senders can split the transaction fees for that one group signature, instead of paying for one personal signature individually.
Schnorr Signature also improves network privacy and token fungibility. A third-party observer will not be able to detect if a user is sending a multi-signature transaction, since the signature will be in the same format as a single-signature transaction.

4. Economics and supply distribution

The Bitcoin protocol utilizes the Nakamoto consensus, and nodes validate blocks via Proof-of-Work mining. The bitcoin token was not pre-mined, and has a maximum supply of 21 million. The initial reward for a block was 50 BTC per block. Block mining rewards halve every 210,000 blocks. Since the average time for block production on the blockchain is 10 minutes, it implies that the block reward halving events will approximately take place every 4 years.
As of May 12th 2020, the block mining rewards are 6.25 BTC per block. Transaction fees also represent a minor revenue stream for miners.
submitted by D-platform to u/D-platform [link] [comments]

TKEYSPACE — blockchain in your mobile

TKEYSPACE — blockchain in your mobile

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Someone says that the blockchain in the phone is marketing. This is possible for most applications, but not for Tkeycoin. Today we will talk about how the blockchain works in the TkeySpace app.
Who else is not in the topic, TkeySpace is a financial application for decentralized and efficient management of various cryptocurrencies, based on a distributed architecture without using a client-server.
In simple words, it is a blockchain in the user’s mobile device that excludes hacking and hacker attacks, and all data is encrypted using modern cryptographic methods.
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Blockchain

Let’s start with the most important thing — the blockchain works on the principles of P2P networks, when there is no central server and each device is both a server and a client, such an organization allows you to maintain the network performance with any number and any combination of available nodes.
For example, there are 12 machines in the network, and anyone can contact anyone. As a client (resource consumer), each of these machines can send requests for the provision of some resources to other machines within this network and receive them. As a server, each machine must process requests from other machines in the network, send what was requested, and perform some auxiliary and administrative functions.
With traditional client-server systems, we can get a completely disabled social network, messenger, or another service, given that we rely on a centralized infrastructure — we have a very specific number of points of failure. If the main data center is damaged due to an earthquake or any other event, access to information will be slowed down or completely disabled.
With a P2P solution, the failure of one network member does not affect the network operation in any way. P2P networks can easily switch to offline mode when the channel is broken — in which it will exist completely independently and without any interaction.
Instead of storing information in a single central point, as traditional recording methods do, multiple copies of the same data are stored in different locations and on different devices on the network, such as computers or mobile devices.

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This means that even if one storage point is damaged or lost, multiple copies remain secure in other locations. Similarly, if one part of the information is changed without the consent of the rightful owners, there are many other copies where the information is correct, which makes the false record invalid.
The information recorded in the blockchain can take any form, whether it is a transfer of money, ownership, transaction, someone’s identity, an agreement between two parties, or even how much electricity a light bulb used.
However, this requires confirmation from multiple devices, such as nodes in the network. Once an agreement, otherwise known as consensus, is reached between these devices to store something on the blockchain — it can’t be challenged, deleted, or changed.
The technology also allows you to perform a truly huge amount of computing in a relatively short time, which even on supercomputers would require, depending on the complexity of the task, many years or even centuries of work. This performance is achieved because a certain global task is divided into a large number of blocks, which are simultaneously performed by hundreds of thousands of devices participating in the project.

P2P messaging and syncing in TkeySpace

TkeySpace is a node of the TKEY network and other supported networks. when you launch the app, your mobile node connects to an extensive network of supported blockchains, syncs with full nodes to validate transactions and incoming information between nodes, so the nodes organize a graph of connections between them.
You can always check the node information in the TkeySpace app in the ⚙ Settings Contact and peer info App Status;

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TkeySpace creates initiating connections to servers registered in the blockchain Protocol as the main ones, from these servers it gets the addresses of nodes to which it can join, in turn, the nodes to which the connection occurred share information about other nodes.

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TkeySpace sends network messages to nodes from supported blockchains in the app to get up-to-date data from the network.
The Protocol uses data structures for communication between nodes, such as block propagation over the network, so before network messages are read, nodes check the “magic number”, check the first bytes, and determine the type of data structure. In the blockchain, the “magic number” is the network ID used to filter messages and block traffic from other p2p networks.
Magic numbers are used in computer science, both for files and protocols. They identify the type of file/data structure. A program that receives such a file/data structure can check the magic number and immediately find out the intended type of this file/data structure.
The first message that your node sends is called a Version Message. In response, the node waits for a Verack message to establish a connection between other peers. The exchange of such messages is called a “handshake”.

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After the “handshake” is set, TkeySpace will start connecting to other nodes in the network to determine the last block at the end of the required blockchain. At this point — nodes request information about blocks they know using GetBlock messages — in response, your node receives an inv (Inventory Message) from another node with the information that it has the information that was requested by the TkeySpace node.
In response to the received message, inv — TkeySpace sends a GetData message containing a list of blocks starting immediately after the last known hash.

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Loading and storing blocks

After exchanging messages, the block information is loaded and transactions are uploaded to your node. To avoid storing tons of information and optimize hard disk space and data processing speed, we use RDBMS — PostgreSQL in full nodes (local computer wallet).
In the TkeySpace mobile app, we use SQLite, and validation takes place by uploading block headers through the Merkle Tree, using the bloom filter — this allows you to optimize the storage of your mobile device as much as possible.
The block header includes its hash, the hash of the previous block, transaction hashes, and additional service information.
Block headers in the Tkeycoin network=84 bytes due to the extension of parameters to support nChains, which will soon be launched in “combat” mode. The titles of the Bitcoin block, Dash, Litecoin=80 bytes.

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And so, let’s continue — application nodes receive information from the blockchain by uploading block headers, all data is synchronized using the Merkle Tree, or rather your node receives and validates information from the Merkle root.
The hash tree was developed in 1979 by Ralph Merkle and named in his honor. The structure of the system has received this name also because it resembles a tree.
The Merkle tree is a complete binary tree with leaf vertexes containing hashes from data blocks, and inner vertexes containing hashes from adding values in child vertexes. The root node of the tree contains a hash from the entire data set, meaning the hash tree is a unidirectional hash function. The Merkle tree is used for the efficient storage of transactions in the cryptocurrency blockchain. It allows you to get a “fingerprint” of all transactions in the block, as well as effectively verify transactions.

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Hash trees have an advantage over hash chains or hash functions. When using hash trees, it is much less expensive to prove that a certain block of data belongs to a set. Since different blocks are often independent data, such as transactions or parts of files, we are interested in being able to check only one block without recalculating the hashes for the other nodes in the tree.
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The Merkle Tree scheme allows you to check whether the hash value of a particular transaction is included in Merkle Root, without having all the other transactions in the block. So by having the transaction, block header, and Merkle Branch for that transaction requested from the full node, the digital wallet can make sure that the transaction was confirmed in a specific block.

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The Merkle tree, which is used to prove that a transaction is included in a block, is also very well scaled. Because each new “layer” added to the tree doubles the total number of “leaves” it can represent. You don’t need a deep tree to compactly prove transaction inclusion, even among blocks with millions of transactions.

Statistical constants and nChains

To support the Tkeycoin cryptocurrency, the TkeySpace application uses additional statistical constants to prevent serialization of Merkle tree hashes, which provides an additional layer of security.
Also, for Tkeycoin, support for multi-chains (nChains) is already included in the TkeySpace app, which will allow you to use the app in the future with most of the features of the TKEY Protocol, including instant transactions.

The Bloom Filter

An additional level of privacy is provided by the bloom filter — which is a probabilistic data structure that allows you to check whether an element belongs to a set.

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The bloom filter looks for whether a particular transaction is linked to Alice, not whether Alice has a specific cryptocurrency. In this way, transactions and received IDs are analyzed through a bloom filter. When “Alice wants to know about transaction X”, an ID is requested for transaction X, which is compared with the filled segments in her bloom filter. If “Yes” is received, the node can get the information and verify the transaction.

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HD support

The multi-currency wallet TkeySpace is based on HD (or hierarchical determinism), a privacy-oriented method for generating and managing addresses. Each wallet address is generated from an xPub wallet (or extended public key). The app is completely anonymous — and individual address is generated for each transaction to accept a particular cryptocurrency. Even for low-level programming, using the same address is negative for the system, not to mention your privacy. We recommend that you always use a new address for transactions to ensure the necessary level of privacy and security.
The EXT_PUBLIC_KEY and EXT_SECRET_KEY values for DASH, Bitcoin, and Litecoin are completely identical. Tkeycoin uses its values, as well as other methods for storing transactions and blocks (RDBMS), and of course — nChains.

Secret key

Wallets in the blockchain have public and private keys.
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Centralized applications usually store users’ private keys on their servers, which makes users’ funds vulnerable to hacker attacks or theft.
A private key is a special combination of characters that provides access to cryptocurrencies stored on the account. Only a person who knows the key can move and spend digital assets.
TkeySpace — stores the encrypted key only on the user’s device and in encrypted form. The encrypted key is displayed as a mnemonic phrase (backup phrase), which is very convenient for users. Unlike complex cryptographic ciphers, the phrase is easy to save or write. A backup keyword provides the maximum level of security.
A mnemonic phrase is 12 or 24 words that are generated using random number entropy. If a phrase consists of 12 words, then the number of possible combinations is 204⁸¹² or 21¹³² — the phrase will have 132 security bits. To restore the wallet, you must enter the mnemonic phrase in strict order, as it was presented after generation.

Result

Now we understand that your application TkeySpace is a node of the blockchain that communicates with other nodes using p2p messages, stores block headers and validate information using the Merkle Tree, verifies transactions, filters information using the bloom filter, and operates completely in a decentralized model. The application code contains all the necessary blockchain settings for communicating with the network, the so-called chain parameters.
TkeySpace is a new generation mobile app. A completely new level of security, easy user-friendly interfaces and all the necessary features that are required to work with cryptocurrency.
submitted by tkeycoin to Tkeycoin_Official [link] [comments]

Groestlcoin 6th Anniversary Release

Introduction

Dear Groestlers, it goes without saying that 2020 has been a difficult time for millions of people worldwide. The groestlcoin team would like to take this opportunity to wish everyone our best to everyone coping with the direct and indirect effects of COVID-19. Let it bring out the best in us all and show that collectively, we can conquer anything.
The centralised banks and our national governments are facing unprecedented times with interest rates worldwide dropping to record lows in places. Rest assured that this can only strengthen the fundamentals of all decentralised cryptocurrencies and the vision that was seeded with Satoshi's Bitcoin whitepaper over 10 years ago. Despite everything that has been thrown at us this year, the show must go on and the team will still progress and advance to continue the momentum that we have developed over the past 6 years.
In addition to this, we'd like to remind you all that this is Groestlcoin's 6th Birthday release! In terms of price there have been some crazy highs and lows over the years (with highs of around $2.60 and lows of $0.000077!), but in terms of value– Groestlcoin just keeps getting more valuable! In these uncertain times, one thing remains clear – Groestlcoin will keep going and keep innovating regardless. On with what has been worked on and completed over the past few months.

UPDATED - Groestlcoin Core 2.18.2

This is a major release of Groestlcoin Core with many protocol level improvements and code optimizations, featuring the technical equivalent of Bitcoin v0.18.2 but with Groestlcoin-specific patches. On a general level, most of what is new is a new 'Groestlcoin-wallet' tool which is now distributed alongside Groestlcoin Core's other executables.
NOTE: The 'Account' API has been removed from this version which was typically used in some tip bots. Please ensure you check the release notes from 2.17.2 for details on replacing this functionality.

How to Upgrade?

Windows
If you are running an older version, shut it down. Wait until it has completely shut down (which might take a few minutes for older versions), then run the installer.
OSX
If you are running an older version, shut it down. Wait until it has completely shut down (which might take a few minutes for older versions), run the dmg and drag Groestlcoin Core to Applications.
Ubuntu
http://groestlcoin.org/forum/index.php?topic=441.0

Other Linux

http://groestlcoin.org/forum/index.php?topic=97.0

Download

Download the Windows Installer (64 bit) here
Download the Windows Installer (32 bit) here
Download the Windows binaries (64 bit) here
Download the Windows binaries (32 bit) here
Download the OSX Installer here
Download the OSX binaries here
Download the Linux binaries (64 bit) here
Download the Linux binaries (32 bit) here
Download the ARM Linux binaries (64 bit) here
Download the ARM Linux binaries (32 bit) here

Source

ALL NEW - Groestlcoin Moonshine iOS/Android Wallet

Built with React Native, Moonshine utilizes Electrum-GRS's JSON-RPC methods to interact with the Groestlcoin network.
GRS Moonshine's intended use is as a hot wallet. Meaning, your keys are only as safe as the device you install this wallet on. As with any hot wallet, please ensure that you keep only a small, responsible amount of Groestlcoin on it at any given time.

Features

Download

iOS
Android

Source

ALL NEW! – HODL GRS Android Wallet

HODL GRS connects directly to the Groestlcoin network using SPV mode and doesn't rely on servers that can be hacked or disabled.
HODL GRS utilizes AES hardware encryption, app sandboxing, and the latest security features to protect users from malware, browser security holes, and even physical theft. Private keys are stored only in the secure enclave of the user's phone, inaccessible to anyone other than the user.
Simplicity and ease-of-use is the core design principle of HODL GRS. A simple recovery phrase (which we call a Backup Recovery Key) is all that is needed to restore the user's wallet if they ever lose or replace their device. HODL GRS is deterministic, which means the user's balance and transaction history can be recovered just from the backup recovery key.

Features

Download

Main Release (Main Net)
Testnet Release

Source

ALL NEW! – GroestlcoinSeed Savior

Groestlcoin Seed Savior is a tool for recovering BIP39 seed phrases.
This tool is meant to help users with recovering a slightly incorrect Groestlcoin mnemonic phrase (AKA backup or seed). You can enter an existing BIP39 mnemonic and get derived addresses in various formats.
To find out if one of the suggested addresses is the right one, you can click on the suggested address to check the address' transaction history on a block explorer.

Features

Live Version (Not Recommended)

https://www.groestlcoin.org/recovery/

Download

https://github.com/Groestlcoin/mnemonic-recovery/archive/master.zip

Source

ALL NEW! – Vanity Search Vanity Address Generator

NOTE: NVidia GPU or any CPU only. AMD graphics cards will not work with this address generator.
VanitySearch is a command-line Segwit-capable vanity Groestlcoin address generator. Add unique flair when you tell people to send Groestlcoin. Alternatively, VanitySearch can be used to generate random addresses offline.
If you're tired of the random, cryptic addresses generated by regular groestlcoin clients, then VanitySearch is the right choice for you to create a more personalized address.
VanitySearch is a groestlcoin address prefix finder. If you want to generate safe private keys, use the -s option to enter your passphrase which will be used for generating a base key as for BIP38 standard (VanitySearch.exe -s "My PassPhrase" FXPref). You can also use VanitySearch.exe -ps "My PassPhrase" which will add a crypto secure seed to your passphrase.
VanitySearch may not compute a good grid size for your GPU, so try different values using -g option in order to get the best performances. If you want to use GPUs and CPUs together, you may have best performances by keeping one CPU core for handling GPU(s)/CPU exchanges (use -t option to set the number of CPU threads).

Features

Usage

https://github.com/Groestlcoin/VanitySearch#usage

Download

Source

ALL NEW! – Groestlcoin EasyVanity 2020

Groestlcoin EasyVanity 2020 is a windows app built from the ground-up and makes it easier than ever before to create your very own bespoke bech32 address(es) when whilst not connected to the internet.
If you're tired of the random, cryptic bech32 addresses generated by regular Groestlcoin clients, then Groestlcoin EasyVanity2020 is the right choice for you to create a more personalised bech32 address. This 2020 version uses the new VanitySearch to generate not only legacy addresses (F prefix) but also Bech32 addresses (grs1 prefix).

Features

Download

Source

Remastered! – Groestlcoin WPF Desktop Wallet (v2.19.0.18)

Groestlcoin WPF is an alternative full node client with optional lightweight 'thin-client' mode based on WPF. Windows Presentation Foundation (WPF) is one of Microsoft's latest approaches to a GUI framework, used with the .NET framework. Its main advantages over the original Groestlcoin client include support for exporting blockchain.dat and including a lite wallet mode.
This wallet was previously deprecated but has been brought back to life with modern standards.

Features

Remastered Improvements

Download

Source

ALL NEW! – BIP39 Key Tool

Groestlcoin BIP39 Key Tool is a GUI interface for generating Groestlcoin public and private keys. It is a standalone tool which can be used offline.

Features

Download

Windows
Linux :
 pip3 install -r requirements.txt python3 bip39\_gui.py 

Source

ALL NEW! – Electrum Personal Server

Groestlcoin Electrum Personal Server aims to make using Electrum Groestlcoin wallet more secure and more private. It makes it easy to connect your Electrum-GRS wallet to your own full node.
It is an implementation of the Electrum-grs server protocol which fulfils the specific need of using the Electrum-grs wallet backed by a full node, but without the heavyweight server backend, for a single user. It allows the user to benefit from all Groestlcoin Core's resource-saving features like pruning, blocks only and disabled txindex. All Electrum-GRS's feature-richness like hardware wallet integration, multi-signature wallets, offline signing, seed recovery phrases, coin control and so on can still be used, but connected only to the user's own full node.
Full node wallets are important in Groestlcoin because they are a big part of what makes the system be trust-less. No longer do people have to trust a financial institution like a bank or PayPal, they can run software on their own computers. If Groestlcoin is digital gold, then a full node wallet is your own personal goldsmith who checks for you that received payments are genuine.
Full node wallets are also important for privacy. Using Electrum-GRS under default configuration requires it to send (hashes of) all your Groestlcoin addresses to some server. That server can then easily spy on your transactions. Full node wallets like Groestlcoin Electrum Personal Server would download the entire blockchain and scan it for the user's own addresses, and therefore don't reveal to anyone else which Groestlcoin addresses they are interested in.
Groestlcoin Electrum Personal Server can also broadcast transactions through Tor which improves privacy by resisting traffic analysis for broadcasted transactions which can link the IP address of the user to the transaction. If enabled this would happen transparently whenever the user simply clicks "Send" on a transaction in Electrum-grs wallet.
Note: Currently Groestlcoin Electrum Personal Server can only accept one connection at a time.

Features

Download

Windows
Linux / OSX (Instructions)

Source

UPDATED – Android Wallet 7.38.1 - Main Net + Test Net

The app allows you to send and receive Groestlcoin on your device using QR codes and URI links.
When using this app, please back up your wallet and email them to yourself! This will save your wallet in a password protected file. Then your coins can be retrieved even if you lose your phone.

Changes

Download

Main Net
Main Net (FDroid)
Test Net

Source

UPDATED – Groestlcoin Sentinel 3.5.06 (Android)

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 wallet.
Groestlcoin Sentinel is a fork of Groestlcoin Samourai Wallet with all spending and transaction building code removed.

Changes

Download

Source

UPDATED – P2Pool Test Net

Changes

Download

Pre-Hosted Testnet P2Pool is available via http://testp2pool.groestlcoin.org:21330/static/

Source

submitted by Yokomoko_Saleen to groestlcoin [link] [comments]

Which type of curren(t) do you want to see(cy)? A analysis of the intention behind bitcoin(s). [Part 2]

Part 1
It's been a bit of time since the first post during which I believe things have crystallised further as to the intentions of the three primary bitcoin variants. I was going to go on a long winded journey to try to weave together the various bits and pieces to let the reader discern from themselves but there's simply too much material that needs to be covered and the effort that it would require is not something that I can invest right now.
Firstly we must define what bitcoin actually is. Many people think of bitcoin as a unit of a digital currency like a dollar in your bank but without a physical substrate. That's kind of correct as a way to explain its likeness to something many people are familiar with but instead it's a bit more nuanced than that. If we look at a wallet from 2011 that has never moved any coins, we can find that there are now multiple "bitcoins" on multiple different blockchains. This post will discuss the main three variants which are Bitcoin Core, Bitcoin Cash and Bitcoin SV. In this respect many people are still hotly debating which is the REAL bitcoin variant and which bitcoins you want to be "investing" in.
The genius of bitcoin was not in defining a class of non physical objects to send around. Why bitcoin was so revolutionary is that it combined cryptography, economics, law, computer science, networking, mathematics, etc. and created a protocol which was basically a rule set to be followed which creates a game of incentives that provides security to a p2p network to prevent double spends. The game theory is extremely important to understand. When a transaction is made on the bitcoin network your wallet essentially generates a string of characters which includes your public cryptographic key, a signature which is derived from the private key:pub key pair, the hash of the previous block and an address derived from a public key of the person you want to send the coins to. Because each transaction includes the hash of the previous block (a hash is something that will always generate the same 64 character string result from EXACTLY the same data inputs) the blocks are literally chained together. Bitcoin and the blockchain are thus defined in the technical white paper which accompanied the release client as a chain of digital signatures.
The miners validate transactions on the network and compete with one another to detect double spends on the network. If a miner finds the correct solution to the current block (and in doing so is the one who writes all the transactions that have elapsed since the last block was found, in to the next block) says that a transaction is confirmed but then the rest of the network disagree that the transactions occurred in the order that this miner says (for double spends), then the network will reject the version of the blockchain that that miner is working on. In that respect the miners are incentivised to check each other's work and ensure the majority are working on the correct version of the chain. The miners are thus bound by the game theoretical design of NAKAMOTO CONSENSUS and the ENFORCES of the rule set. It is important to note the term ENFORCER rather than RULE CREATOR as this is defined in the white paper which is a document copyrighted by Satoshi Nakamoto in 2009.

Now if we look at the three primary variants of bitcoin understanding these important defining characteristics of what the bitcoin protocol actually is we can make an argument that the variants that changed some of these defining attributes as no longer being bitcoin rather than trying to argue based off market appraisal which is essentially defining bitcoin as a social media consensus rather than a set in stone rule set.
BITCOIN CORE: On first examination Bitcoin Core appears to be the incumbent bitcoin that many are being lead to believe is the "true" bitcoin and the others are knock off scams. The outward stated rationale behind the bitcoin core variant is that computational resources, bandwidth, storage are scarce and that before increasing the size of each block to allow for more transactions we should be increasing the efficiency with which the data being fed in to a block is stored. In order to achieve this one of the first suggested implementations was a process known as SegWit (segregating the witness data). This means that when you construct a bitcoin transaction, in the header of the tx, instead of the inputs being public key and a signature + Hash + address(to), the signature data is moved outside of header as this can save space within the header and allow more transactions to fill the block. More of the history of the proposal can be read about here (bearing in mind that article is published by the bitcoinmagazine which is founded by ethereum devs Vitalik and Mihai and can't necessarily be trusted to give an unbiased record of events). The idea of a segwit like solution was proposed as early as 2012 by the likes of Greg Maxwell and Luke Dash Jnr and Peter Todd in an apparent effort to "FIX" transaction malleability and enable side chains. Those familiar with the motto "problem reaction solution" may understand here that the problem being presented may not always be an authentic problem and it may actually just be necessary preparation for implementing a desired solution.
The real technical arguments as to whether moving signature data outside of the transaction in the header actually invalidates the definition of bitcoin as being a chain of digital signatures is outside my realm of expertise but instead we can examine the character of the individuals and groups involved in endorsing such a solution. Greg Maxwell is a hard to know individual that has been involved with bitcoin since its very early days but in some articles he portrays himself as portrays himself as one of bitcoins harshest earliest critics. Before that he worked with Mozilla and Wikipedia and a few mentions of him can be found on some old linux sites or such. He has no entry on wikipedia other than a non hyperlinked listing as the CTO of Blockstream. Blockstream was a company founded by Greg Maxwell and Adam Back, but in business registration documents only Adam Back is listed as the business contact but registered by James Murdock as the agent. They received funding from a number of VC firms but also Joi Ito and Reid Hoffman and there are suggestions that MIT media labs and the Digital Currency Initiative. For those paying attention Joi Ito and Reid Hoffman have links to Jeffrey Epstein and his offsider Ghislaine Maxwell.

Ghislaine is the daughter of publishing tycoon and fraudster Robert Maxwell (Ján Ludvík Hyman Binyamin Hoch, a yiddish orthodox czech). It is emerging that the Maxwells are implicated with Mossad and involved in many different psyops throughout the last decades. Greg Maxwell is verified as nullc but a few months ago was outed using sock puppets as another reddit user contrarian__ who also admits to being Jewish in one of his comments as the former. Greg has had a colourful history with his roll as a bitcoin core developer successfully ousting two of the developers put there by Satoshi (Gavin Andreson and Mike Hearn) and being referred to by Andreson as a toxic troll with counterpart Samon Mow. At this point rather than crafting the narrative around Greg, I will provide a few links for the reader to assess on their own time:
  1. https://coinspice.io/news/btc-dev-gregory-maxwell-fake-social-media-account-accusations-nonsense/
  2. https://www.trustnodes.com/2017/06/06/making-gregory-maxwell-bitcoin-core-committer-huge-mistake-says-gavin-andresen
  3. https://www.ccn.com/gavin-andresen-samson-mow-and-greg-maxwell-toxic-trolls//
  4. https://www.nytimes.com/2016/01/17/business/dealbook/the-bitcoin-believer-who-gave-up.html
  5. https://www.coindesk.com/mozilla-accepting-bitcoin-donations
  6. https://spectrum.ieee.org/tech-talk/computing/networks/the-bitcoin-for-is-a-coup
  7. https://www.reddit.com/btc/comments/68pusp/gavin_andresen_on_twitter_im_looking_for_beta/dh1cmfl/
  8. https://www.reddit.com/btc/comments/d14qee/can_someone_post_the_details_of_the_relationships/?ref=tokendaily
  9. https://www.coindesk.com/court-docs-detail-sexual-misconduct-allegations-against-bitcoin-consultant-peter-todd
  10. https://coinspice.io/news/billionaire-jeffrey-epstein-btc-maximalist-bitcoin-is-a-store-of-value-not-a-currency/
  11. https://www.dailymail.co.uk/news/article-7579851/More-300-paedophiles-arrested-worldwide-massive-child-abuse-website-taken-down.html
  12. https://news.bitcoin.com/risks-segregated-witness-opening-door-mining-cartels-undermine-bitcoin-network/
  13. https://micky.com.au/craig-wrights-crackpot-bitcoin-theory-covered-by-uks-financial-times/
  14. https://www.reddit.com/btc/comments/74se80/wikipedia_admins_gregory_maxwell_of_blockstream/

Now I could just go on dumping more and more articles but that doesn't really weave it all together. Essentially it is very well possible that the 'FIX' of bitcoin proposed with SegWit was done by those who are moral reprobates who have been rubbing shoulders money launderers and human traffickers. Gregory Maxwell was removed from wikipedia, worked with Mozilla who donated a quarter of a million to MIT media labs and had relationship with Joi Ito, the company he founded received funding from people associated with Epstein who have demonstrated their poor character and dishonesty and attempted to wage toxic wars against those early bitcoin developers who wished to scale bitcoin as per the white paper and without changing consensus rules or signature structures.
The argument that BTC is bitcoin because the exchanges and the market have chosen is not necessarily a logical supposition when the vast majority of the money that has flown in to inflate the price of BTC comes from a cryptographic USD token that was created by Brock Pierce (Might Ducks child stahollywood pedo scandal Digital Entertainment Network) who attended Jeffrey Epstein's Island for conferences. The group Tether who issues the USDT has been getting nailed by the New York Attorney General office with claims of $1.4 trillion in damages from their dodgey practices. Brock Pierce has since distanced himself from Tether but Blockstream still works closely with them and they are now exploring issuing tether on the ethereum network. Tether lost it's US banking partner in early 2017 before the monstrous run up for bitcoin prices. Afterwards they alleged they had full reserves of USD however, they were never audited and were printing hundreds of millions of dollars of tether each week during peak mania which was used to buy bitcoin (which was then used as collateral to issue more tether against the bitcoin they bought at a value they inflated). Around $30m in USDT is crossing between China to Russia daily and when some of the groups also related to USDT/Tether were raided they found them in possession of hundreds of thousands of dollars worth of counterfeit physical US bills.
Because of all this it then becomes important to reassess the arguments that were made for the implementation of pegged sidechains, segregated witnesses and other second layer solutions. If preventing the bitcoin blockchain from bloating was the main argument for second layer solutions, what was the plan for scaling the data related to the records of transactions that occur on the second layer. You will then need to rely on less robust ways of securing the second layer than Proof Of Work but still have the same amount of data to contend with, unless there was plans all along for second layer solutions to enable records to be deleted /pruned to facilitate money laundering and violation of laws put in place to prevent banking secrecy etc.
There's much more to it as well and I encourage anyone interested to go digging on their own in to this murky cesspit. Although I know very well what sort of stuff Epstein has been up to I have been out of the loop and haven't familiarised myself with everyone involved in his network that is coming to light.
Stay tuned for part 3 which will be an analysis of the shit show that is the Bitcoin Cash variant...
submitted by whipnil to C_S_T [link] [comments]

Bitcoin: Beyond The Bubble - Full Documentary - YouTube Blockchain/Bitcoin for beginners 6: blocks and mining, content and creation of bitcoin blocks How Bitcoin Wallets Work (Public & Private Key Explained ... Bitcoin 101 - Merkle Roots and Merkle Trees - Bitcoin ... Bitcoin Transaction Details - Part 2

Block in Blockchain consist of main two things, one is block header and other transactions that get stored in that block. Same structure apply to bitcoin as well but with few more additional items and that we will discuss in this blog post. Pre-Requisites. Become your self familiarize with Merkle tree using this post where the basics of Merkle tree is discussed and highlighted the features ... Block header structure. The block header component has a unique identifier called the block header hash. Each block header is comprised out of three main components: the previous block hash, the timestamp, difficulty and nonce (information about mining), and the Markle Tree Root. The version number is used to keep track of upgrades and changes in the Bitcoin protocol. The previous header hash ... learn me a bitcoin. By Greg Walker. Home; Beginners ; Technical; Explorer; $13,010.81/BTC Buy. Subscribe. Tools. Hash256. Hash160. Reverse Bytes. Hexadecimal. Satoshis. Block Header. A summary of the data in the block. A block header is like the metadata at the top of a block of transactions. The fields in the block header provide a unique summary of the entire block. Example. Here’s the ... Block header structure. The block header component has a unique identifier called the block header hash. Each block header is comprised out of three main components: the previous block hash, the timestamp, difficulty and nonce (information about mining), and the Markle Tree Root. The version number is used to keep track of upgrades and changes in the Bitcoin protocol. The previous header hash ... The main way of identifying a block in the blockchain is via its block header hash. The block header hash is calculated by running the block header through the SHA256 algorithm twice. A block header hash is not sent through the network but instead is calculated by each node as part of the verification process of each block.

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Bitcoin: Beyond The Bubble - Full Documentary - YouTube

The mechanics of a bitcoin transaction block chain, which is a construct that is generated by bitcoin miners and functions as a global ledger for recording a... Wallets in cryptocurrency work in a weird way. They also have some weird properties like: they can be created offline and be used directly. Whut? Let's see h... In this video we introduce the basic concepts behind how new blocks are created in the Bitcoin blockchain. We start by taking another look at the blockchain.info website to see some sample blocks ... Thanks for watching! For donations: Bitcoin - 1CpGMM8Ag8gNYL3FffusVqEBUvHyYenTP8 Blockchain/Bitcoin for beginners 6: blocks and mining, content and creation of bitcoin ... Merkle Roots and Merkle Trees - Bitcoin Coding and Software - The Block Header - Duration: 24:18. CRI ...

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