Total BTC Fees for On-Chain Transactions ... - Bitcoin Insider

new paper: Proof of Activity: Extending Bitcoin’s Proof of Work via Proof of Stake by Iddo Bentov, Charles Lee, Alex Mizrahi, and Meni Rosenfeld

submitted by jakob_Z to Bitcoin [link] [comments]

My name is Meni Rosenfeld and I support Bitcoin Core.

Just wanted to say it. Seems important.
I am not a Bitcoin Core developer or any kind of developer. I am also not affiliated with Blockstream or received any sort of payment or incentive from them.
I did meet several of the people from Blockstream (before it existed) in various conferences, such as Pieter Wuille, Gregory Maxwell and Adam Back, and I think they're all very nice people (earliest was Pieter, whom I've met in Prague in November 2011). For reference, I've met Roger Ver in New York in August 2011, and he also seemed nice.
Lest I be suspected of being a random troll paid to feign support for Core... Look me up. I've been involved with Bitcoin since March 2011, most of that time in full capacity. I'm best known for my work on mining pool reward methods, and for my work on promoting Bitcoin in Israel. During this time I've also occasionally posted about how I believe Bitcoin should face its challenges going forward, and notably, my views haven't changed considerably over the years. For example, I support Core's position that scalability should be derived primarily from micropayment-channel-based solutions, and have since 2012 (see https://bitcointalk.org/index.php?topic=91732.0). So I cannot be accused of promoting that view out of some vested interest.
I do not condone the moderation policy of /bitcoin which rejects discussions about alternative protocols.
I do not believe the conspiracy theory which suggests that Bitcoin Core is interchangeable with Blockstream.
I do believe there's room for a modest block size increase, perhaps more so than most of my fellow Core supporters. But I also believe it is important to respect the analysis of technical people who have been with Bitcoin since the beginning - in particular, with respect to the potential danger of hard forks.
Despite the drama regarding blocks being full, I have not yet been personally severely affected by the phenomenon. I believe that with the immediate effective block size increase that SegWit offers, coupled with the eventual advent of micropayment-channel-based solutions, I may never have to be. I also believe that if for some reason these solutions fail, we can always reopen the issue and find solutions as the problems become relevant. As such, I cannot understand why anyone in their right minds would oppose Segwit.
I believe that Bitcoin Unlimited is dangerous. I believe that even if it works as planned, it gives way too much power to miners, at the expense of other participants in the Bitcoin network. I also believe that it will not work as planned, that it is buggy and exploitable, and that it has not been thoroughly researched and tested, as should fit a change of this magnitude.
I believe that the power to change the Bitcoin protocol should, and does, rest in the hands of the economic majority of people who use Bitcoin and give it value. I believe that miners should not and do not have the power to dictate protocol changes unilaterally.
I believe that in case of disagreement about changes, the default should be sticking with the current protocol until agreement is reached, rather than rushing into making changes.
I believe that if all else fails and the disagreement cannot be reconciled, there should be a responsible split of the network into two, with both sides working to ensure a clean, uneventful split, and both sides respecting each other's right to coexist.
I have written a series of blog posts about that last point:
How I learned to stop worrying and love the fork
I disapprove of Bitcoin splitting, but I’ll defend to the death its right to do it
And God said, “Let there be a split!” and there was a split.
EDIT: Ok, there have been a lot of comments. Thanks for the lively discussion. But its 3:10 AM here now, I need to sleep and tomorrow I'll probably need to work. I'll try address as much as possible.
EDIT 2: Please see my followup comment.
submitted by MeniRosenfeld to btc [link] [comments]

It's time for a break: About the recent mess & temporary new rules

Unfortunately, I was on vacation this weekend, so I was unable to prevent /Bitcoin from becoming messy. Sorry about that. I and other moderators more-or-less cleaned it up. Report anything that we missed.
Because people are still probably in a "troll-happy" mood from the lack of moderation, moderation will be increased for a while. Everyone needs some time to calm down. In particular, posts about anything especially emotionally-charged will be deleted unless they introduce some very substantial new ideas about the subject. This includes the max block size debate (any side) and /Bitcoin moderation. Also, people are continuously spamming links to inferior clones of /Bitcoin and the XT subreddit -- these links will be removed and the posters banned unless the links are remarkably appropriate for the given situation. When this sticky is removed, the rules will return to what they were previously.
It is possible that some people have been or will be banned too readily due to the increased moderation. If this happens to you, mail /Bitcoin with a justification of your actions, then wait 2 days and mail again if there's no satisfactory response, then wait 4 days, then 8, 16, 32, etc. If your mail to /Bitcoin is too high-volume, we may block all further mail from you, which will make it impossible for your to appeal your ban.

About XT

/Bitcoin exists to serve Bitcoin. XT will, if/when its hardfork is activated, diverge from Bitcoin and create a separate network/currency. Therefore, it and services that support it should not be allowed on /Bitcoin. In the extremely unlikely event that the vast majority of the Bitcoin economy switches to XT and there is a strong perception that XT is the true Bitcoin, then the situation will flip and we should allow only submissions related to XT. In that case, the definition of "Bitcoin" will have changed. It doesn't make sense to support two incompatible networks/currencies -- there's only one Bitcoin, and /Bitcoin serves only Bitcoin.
If a hardfork has near-unanimous agreement from Bitcoin experts and it's also supported by the vast majority of Bitcoin users and companies, we can predict with high accuracy that this new network/currency will take over the economy and become the new definition of Bitcoin. (Miners don't matter in this, and it's not any sort of vote.) This sort of hardfork can probably be adopted on /Bitcoin as soon as it has been determined that the hardfork is not absolutely against the spirit of Bitcoin (inflating out-of-schedule, for example). For right now, there will always be too much controversy around any hardfork that increases the max block size, but this will probably change as there's more debate and research, and as block space actually becomes more scarce. I could see some kind of increase gaining consensus in as soon as 6 months, though it would have to be much smaller than the increase in XT for ~everyone to agree on it so soon.
There's a substantial difference between discussion of a proposed Bitcoin hardfork (which was previously always allowed here, even though I strongly disagree with many things posted) and promoting software that is programmed to diverge into a competing network/currency. The latter is clearly against the established rules of /Bitcoin, and while Bitcoin's technology will continue working fine no matter what people do, even the attempt at splitting Bitcoin up like this will harm the Bitcoin ecosystem and economy.

Why is XT considered an altcoin even though it hasn't broken away from Bitcoin yet?

Because it is intentionally programmed to diverge from Bitcoin, I don't consider it to be important that XT is not distinct from Bitcoin quite yet. If someone created a fork of Bitcoin Core that allowed miners to continue mining 25 BTC per block forever, would that be "Bitcoin" even though it doesn't split from the Bitcoin currency/network quite yet? (I'd say no.)

Can I still talk about hard fork proposals on /Bitcoin?

Right now, not unless you have something really new and substantial to say.
After this sticky is removed, it will be OK to discuss any hardfork to Bitcoin, but not any software that hardforks without consensus, since that software is not Bitcoin.

If XT is an altcoin then why aren't sidechains or Lightning altcoins?

/Bitcoin is about the Bitcoin currency and network. Lightning allows you to move the Bitcoin currency. Sidechains are on-topic in general because they are a possibly-useful addition to the Bitcoin network. It is possible that some specific sidechains might not be on-topic -- this isn't clear to me yet.
XT is programmed to create a separate currency and network, so it is not Bitcoin.

How do you know that there is no consensus?

Consensus is a high bar. It is not the same as a majority. In general, consensus means that there is near-unanimity. In the very particular case of a hardfork, "consensus" means "there is no noticeable probability that the hardfork will cause the Bitcoin economy to split into two or more non-negligible pieces".
I know almost for certain that there is no consensus to the change in XT because Bitcoin core developers Wladamir, Greg, and Pieter are opposed to it. That's enough to block consensus. And it works both ways: if Gavin and Mike are strongly opposed to Pieter's BIP, then this will also block consensus on that BIP.
Other than the core devs, big Bitcoin companies (especially Coinbase, BitPay, and exchanges) could block consensus, as could large groups of average users who are collectively capable of making reasonable arguments and exerting economic force (probably not just random unknown people complaining about nothing).
Even though consensus is such a high bar, I think that in practice any hardfork that gets consensus among the Bitcoin Core devs and makes it into Bitcoin Core has a good chance of succeeding. But again, the developers would just be spearheading the effort, and many others could block them if necessary.

But with such a high bar, 8 MB blocks will be impossible!

If consensus can never be reached on one particular hardfork proposal, then the hardfork should never occur. Just because you want something doesn't mean that it's ever reasonable for you to hijack Bitcoin from the people who don't want it, even if your side is the majority (which it isn't in this case). This isn't some democratic country where you can always get your way with sufficient politicking. Get consensus, live without the change, or create your own altcoin.
Hard forks are supposed to be hard. While some hard forks will probably be necessary in the long run, these hard forks will need to have consensus and be done properly or Bitcoin will die due to the economy being constantly shattered into several pieces, or as a side-effect of forcing through technically unsound changes that the majority of experts disagree with (like XT's 8MB block size).

Don't most experts want 8 MB blocks soon?

Not by any reasonable idea of "most experts" I can think of. For example, among people with expert flair on /Bitcoin, AFAIK any large near-term increase is opposed by nullc, petertodd, TheBlueMatt, luke-jr, pwuille, adam3us, maaku7, and laanwj. A large near-term increase is supported by gavinandresen, jgarzik, mike_hearn, and MeniRosenfeld. (Those 12 people are everyone with expert flair.)
I've heard concerns that some experts who oppose any large near-term increase have conflicts of interest. But many of them have been expressing the same concerns for years, so it's unlikely that any recent possible conflict of interest is influencing them. Also, if they believed that increasing the max block size would help Bitcoin as a whole, what reason would they have to prevent this? I don't see the incentive.
We don't need to trust the above list of experts, of course. But I for one have found the conservative position's arguments to be much more convincing than the huge-increase position's arguments. It's not reasonable to say, "You know a lot more than I do, and I don't see any fault in your arguments, but you must be trying to trick me due to this potential conflict of interest, so I'm going to ignore you."

Who are you working for?

I am not an employee of anyone but myself. As far as I know my only incentives for engaging in this policy are to make Bitcoin as strong as possible for ideological reasons, and in the long-term to increase the Bitcoin price. When I make policies, I do so because I believe that they are right. I am not being paid for my work on /Bitcoin or for creating certain policies.
It would have been far easier for me to simply allow XT. If I was a politician or a business, I probably would have bowed to community demands already. And on several occasions I have very seriously considered the possibility that I could be wrong here and the community right. But in the end I just don't see any way to both reasonably and consistently deal with XT and cases similar to XT except to ban them on /Bitcoin. Additionally, I am further motivated by my knowledge that a "hostile hardfork" like the one in XT is very harmful for Bitcoin no matter what the change entails, and that the change in XT is in fact amazingly bad.

See also

See my previous posts on this subject and the discussion in their child comments. Keep in mind that my comments are often downvoted to the point of being hidden by default.
Also, someone who could be Satoshi posted here. This email address was actually used by Satoshi before he left, and the email apparently did come from that email address legitimately (not a spoof). Whether he's actually Satoshi or not, I agree with what he's saying.

About majoritarianism

Just because many people want something doesn't make it right. There is example after example of this in history. You might reasonably believe that democracy is the best we can do in government (though I disagree), but it's not the best we can do with private and independent forums on the free market.
If you disagree with /Bitcoin policy, you can do one of these things:
Do not violate our rules just because you disagree with them. This will get you banned from /Bitcoin, and evading this ban will get you (and maybe your IP) banned from Reddit entirely.
If 90% of /Bitcoin users find these policies to be intolerable, then I want these 90% of /Bitcoin users to leave. Both /Bitcoin and these people will be happier for it. I do not want these people to make threads breaking the rules, demanding change, asking for upvotes, making personal attacks against moderators, etc. Without some real argument, you're not going to convince anyone with any brains -- you're just wasting your time and ours. The temporary rules against blocksize and moderation discussion are in part designed to encourage people who should leave /Bitcoin to actually do so so that /Bitcoin can get back to the business of discussing Bitcoin news in peace.
The purpose of moderation is to make the community a good one, which sometimes includes causing people to leave.

This thread

You can post comments about moderation policy here, but nowhere else.
submitted by theymos to Bitcoin [link] [comments]

Live Bitcoin Interview 5 - Meni Rosenfeld

https://www.facebook.com/events/442643202989023/
Join me and Meni Rosenfeld, the most known Bitcoiner in Israel and Chairman of the Israeli Bitcoin Association, for an in-depth interview.
The interview will be conducted live on our new Youtube channel: https://www.youtube.com/channel/UCC52cnag992fznwg_uPSzcQ/ (send me your email address or subscribe on youtube to be notified on further interviews, I promise not to spam you).
If you have any questions for Meni please send them in advance. See you soon!
Aug 13, 1:30-3:30 pm Israel time
submitted by ripper2345 to CryptoCurrency [link] [comments]

Live Bitcoin Interview 5 - Meni Rosenfeld

https://www.facebook.com/events/442643202989023/
Join me and Meni Rosenfeld, the most known Bitcoiner in Israel and Chairman of the Israeli Bitcoin Association, for an in-depth interview.
The interview will be conducted live on our new Youtube channel: https://www.youtube.com/channel/UCC52cnag992fznwg_uPSzcQ/ (send me your email address or subscribe on youtube to be notified on further interviews, I promise not to spam you).
If you have any questions for Meni please send them in advance. See you soon!
Aug 13, 1:30-3:30 pm Israel time
submitted by ripper2345 to Bitcoin [link] [comments]

Most alt-coins are NOT secure enough, they exist only for entertainment and speculation

(I believe this needs to be posted to /bitcoin as Bitcoin users/enthusiasts need to know the difference between Bitcoin and other cryptocurrencies. About author: I'm subscribed to /bitcoin since 2011, and have been involved in cryptocurrency security research for several years.)
Let's talk about security aspect of cryptocurrencies. I'm afraid an average user knows very little about this topic: he might know that hashrate is needed to protect the blockchain, and that higher hashrate is better, as it implies that attacker needs to spend more to get control of the blockchain.
But there is a plenty of other kinds of attacks (or, rather, economic models of attacks), some of which have much higher practical significance.
Let's start with something simple: there is a straightforward and rigorous model of double-spending attack under condition that attacker has a fraction of total network's hashrate. I highly recommend Meni Rosenfeld's Analysis of hashrate-based double-spending paper (PDF).
The main takeaway from this paper is that "maximal safe transaction value" is directly proportional to block reward (i.e. amount of coins miners get for each block). It is easy to understand this intuitively: bigger reward means that miners get more money from normal mining, so they will be reluctant to try double-spending attacks. On the other hand, if block reward was negligible, double-spending could be a lucrative source of revenue.
Let's look at numbers: if attacker controls 26% of hashrate and number of confirmations is 6, maximal safe transaction value is 1113 BTC when block reward is 25 BTC. This is pretty cool: you only need to wait 1 hour to make sure you irreversibly received half million USD worth of bitcoins (I assume exchange rate of $450 for 1 Bitcoin).
However, situation is pretty different for alt-coins which have much less valuable block rewards. For example, imagine there is a Foocoin with exchange rate of $1 for 1 Foocoin. If Foocoin's block reward is also 25 foocoins, then max save transaction value for 6 confirmations is only $1113 USD worth of Foocoins. It doesn't look like Foocoin is suitable for commerce, does it?
One could say that Foocoin simply requires larger number of confirmations for larger transactions. But that's wrong: higher number of confirmations helps only under condition that attacker is unable to obtain more than 50% of total hashrate, but for most alt-coins it isn't true.
First of all, let's note that so-called miners simply rent their equipment to "mining pool operators" and are paid in crypto-currency for it. In many cases they don't even care what cryptocurrency they mine as long as they are being paid. See Middlecoin:
This pool automatically mines the most profitable scrypt coin, automatically exchanges those coins for bitcoins, and pays out entirely in bitcoins.
So, miners who mine using Middlecoin do not know if their equipment is being used to mine Litecoins or Dogecoins or something else. And they wouldn't care if it is used for attacks on alt-coins, as they are being paid in bitcoins.
Let's consider a scenario where Middlecoin-like pool has higher hashrate than Foocoin, e.g. Middlecoin (not Middlecoin specifically, but any pool like that) has 20 GH/s, while Foocoin has 10 GH/s. Here's how one can profit from it:
  1. Buy $1M worth of Foocoins, get them into your wallet.
  2. Make an agreement with Middlecoin: you rent they hashrate for a couple of hours, paying them in bitcoin, slightly above what most profitable alt-coin yields.
  3. Send your foocoins to exchange Bar.
  4. Start mining a private chain which has a double-spend transaction which sends coins to exchange Baz.
  5. After your transaction gets 10 confirmations on the normal chain, convert foocoins to bitcoins on Bar and withdraw them immediately.
  6. After withdrawal transaction is confirmed on Bitcoin network (and thus cannot be reversed), you release the private chain you have mined, causing reorganization. You should have mined 20 blocks by then under if Middlecoin has hashrate which is twice higher than normal Foocoin's hashrate.
  7. Your deposit to exchange Baz is now confirmed, converl your foocoins to bitcoins again, and withdraw immediately.
  8. A day later 20 blocks you have mined will get mature, and you'll be able to sell them too.
If Foocoin price doesn't change in process, you can get approximately $1M profit on this attack, as cost of renting a mining pool is approximately equal to value of mined blocks.
In practice, you'll lose some money due to lack of liquidity on exchanges, so profit will be less than $1M.
The conclusion we get from this analysis is that alt-coins which have only a small fraction of total hashrate for a certain mining algorithm are extremely non-secure. And they cannot grow big: as soon as exchanges will have enough liquidity, it will be possible to perform the attack I described, which will result in the price drop.
So almost all alt-coins are simply not suitable for any kind of "real economy" applications. They are doomed to have high volatility, shallow markets, low "max safe transaction value".
One can't deny the fact that it is possible to make money on alt-coins. But that's just gambling. And people who create new alt-coins are in same position as people who build casinos. It is a business, but it is the entertainment sector, not in 'real economy' or 'financial' sectors as some people are trying to pretend.
Bitcoin is one of few cryptocurrencies which are actually serious. It isn't perfect, but attacking Bitcoin is very hard, so transactions worth millions of dollars can be confirmed in matter of hours. Same cannot be said about alt-coins, and this situation won't change unless new cryptocurrency designs will be found.
If there is an alt-coin which is more-or-less secure, it is probably Litecoin. Its hashrate is a significant fraction of total scrypt hashrate, so attacking Litecoin is hard. Interestingly, at some point Dogecoin's hashrate was higher than Litecoin's but it dropped after block reward have dropped. So, again, block reward is important for security.
This has dire implications for alt-coins which have short block reward schedules. If all coins will be mined in two years, this mean that alt-coin will be dead in two years.
(It's worth noting that same problem might affect Bitcoin in future, like in 10 years or so.)
Now there is a question: Is there a way to make multiple currencies all of which will be secure?
Probably. There are several approaches:
  1. Merged mining: The idea is that Bitcoin's proof-of-work can be re-used to mine alt-chains. This makes attacks harder, but hashrate-based double-spending considerations are still applicable, so safety can't be guaranteed... They will be safe only if miners are benevolent.
  2. Side-chains: This needs more research, but it looks like high degree of security is possible as long as you don't care about SPV.
  3. Proof-of-stake and PoW/PoS hybrid: Needs more research, there is some hope. Note that Peercoin's PoS is pretty bad.
  4. Multiple cryptocurrencies in the same blockchain (e.g. colored coins, Mastercoin, Counterparty, Ethereum, Ripple, etc.) will all be equally secure, so I believe this is what we should do instead of spawning a shitload of alt-coins.
submitted by killerstorm to Bitcoin [link] [comments]

Estimation of Miner Hash Rates and Consensus on Blockchains

arXiv:1707.00082
Date: 2017-07-01
Author(s): A. Pinar Ozisik, George Bissias, Brian Levine

Link to Paper


Abstract
We make several contributions that quantify the real-time hash rate and therefore the consensus of a blockchain. We show that by using only the hash value of blocks, we can estimate and measure the hash rate of all miners or individual miners, with quanti able accuracy. We apply our techniques to the Ethereum and Bitcoin blockchains; our solution applies to any proof-of-work-based blockchain that relies on a numeric target for the validation of blocks. We also show that if miners regularly broadcast status reports of their partial proof-of- work, the hash rate estimates are signi cantly more accurate at a cost of slightly higher bandwidth. Whether using only the blockchain, or the additional information in status reports, merchants can use our techniques to quantify in real-time the threat of double-spend attacks.

References
[1] 2015. The Bitcoin Lightning Network: Scalable Off-Chain Instant Payments. https://lightning.network/lightning-network-paper.pdf. (July 2015).
[2] 2016. Gnosis. https://www.gnosis.pm. (November 2016).
[3] Asaph Azaria, Ariel Ekblaw, Thiago Vieira, and Andrew Lippman. 2016. "MedRec: Using Blockchain for Medical Data Access and Permission Management. In Proc. Intl. Conf. on Open and Big Data. 25–30.
[4] Adam Back, Matt Corallo, Luke Dashjr, Mark Friedenbach, Gregory Maxwell, Andrew Miller, Andrew Poelstra, Jorge Timón, and Pieter Wuille. 2014. Enabling Blockchain Innovations with Pegged Sidechains. Technical report. (Oct 22 2014).
[5] Simon Barber, Xavier Boyen, Elaine Shi, and Ersin Uzun. 2012. Bitter to better—how to make bitcoin a better currency. In International Conference on Financial Cryptography and Data Security. Springer, 399–414.
[6] Bryan Bishop. 2015. bitcoin-dev mailling list: Weak block thoughts... https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-Septembe011158.html. (Sep 2015).
[7] bitcoin 2015. Confirmation. https://en.bitcoin.it/wiki/Confirmation. (February 2015).
[8] Joseph Bonneau. 2015. How long does it take for a Bitcoin transaction to be confirmed? https://coincenter.org/2015/11/what-does-it-meanfor-a-bitcoin-transaction-to-be-confirmed/. (November 2015).
[9] J. Bonneau, A. Miller, J. Clark, A. Narayanan, J.A. Kroll, and E.W. Felten. 2015. SoK: Research Perspectives and Challenges for Bitcoin and Cryptocurrencies. In IEEE S&P. 104–121. http://doi.org/10.1109/ SP.2015.14
[10] George Casella and Roger L. Berger. 2002. Statistical inference. Brooks Cole, Pacific Grove, CA. http://opac.inria.frecord=b1134456
[11] Kyle Croman et al. 2016. On Scaling Decentralized Blockchains . In Workshop on Bitcoin and Blockchain Research.
[12] Digix. 2017. https://www.dgx.io/. (Last retrieved June 2017).
[13] DigixDAO. 2017. https://www.dgx.io/dgd/. (Last retrieved June 2017).
[14] J. Douceur. 2002. The Sybil Attack. In Proc. Intl Wkshp on Peer-to-Peer Systems (IPTPS).
[15] Bradley Efron. 1982. The jackknife, the bootstrap and other resampling plans. Society for industrial and applied mathematics (SIAM).
[16] Ethash. 2017. https://github.com/ethereum/wiki/wiki/Ethash. (Last retrieved June 2017).
[17] ethereum. Ethereum Homestead Documentation. http://ethdocs.org/en/latest/. (????).
[18] Etheria. 2017. http://etheria.world. (Last retrieved June 2017).
[19] Ittay Eyal and Emin Gün Sirer. 2014. Majority is not enough: Bitcoin mining is vulnerable. Financial Cryptography (2014), 436–454. http://doi.org/10.1007/978-3-662-45472-5_28
[20] William Feller. 1968. An Introduction to Probability Theory and its Applications: Volume I. Vol. 3. John Wiley & Sons London-New YorkSydney-Toronto.
[21] Juan Garay, Aggelos Kiayias, and Nikos Leonardos. 2015. The bitcoin backbone protocol: Analysis and applications. In Annual International Conference on the Theory and Applications of Cryptographic Techniques. Springer, 281–310.
[22] Arthur Gervais, Ghassan O. Karame, Karl Wust, Vasileios Glykantzis, Hubert Ritzdorf, and Srdjan Capkun. 2016. On the Security and Performance of Proof of Work Blockchains. https://eprint.iacr.org/2016/555. (2016).
[23] Hashcash. 2017. https://en.bitcoin.it/wiki/Hashcash. (Last retrieved June 2017).
[24] Ethan Heilman, Leen Alshenibr, Foteini Baldimtsi, Alessandra Scafuro, and Sharon Goldberg. 2017. TumbleBit: An untrusted Bitcoincompatible anonymous payment hub. In Proc. ISOC Network and Distributed System Security Symposium (NDSS).
[25] Svante Janson. 2014. Tail Bounds for Sums of Geometric and Exponential Variable. Technical Report. Uppsala University.
[26] Litecoin. 2017. https://litecoin.org. (Last retrieved June 2017).
[27] Satoshi Nakamoto. 2009. Bitcoin: A Peer-to-Peer Electronic Cash System. https://bitcoin.org/bitcoin.pdf. (May 2009).
[28] A. Pinar Ozisik, Gavin Andresen, George Bissias, Amir Houmansadr, and Brian Neil Levine. 2016. A Secure, Efficient, and Transparent Network Architecture for Bitcoin. Technical Report UM-CS-2016-006. University of Massachusetts, Amherst, MA. https://web.cs.umass.edu/publication/details.php?id=2417
[29] Meni Rosenfeld. 2012. Analysis of hashrate-based double-spending. https://bitcoil.co.il/Doublespend.pdf. (December 2012).
[30] Ayelet Sapirshtein, Yonatan Sompolinsky, and Aviv Zohar. 2015. Optimal Selfish Mining Strategies in Bitcoin. https://arxiv.org/pdf/1507.06183.pdf. (July 2015).
[31] Eli Ben Sasson, Alessandro Chiesa, Christina Garman, Matthew Green, Ian Miers, Eran Tromer, and Madars Virza. 2014. Zerocash: Decentralized Anonymous Payments from Bitcoin. In IEEE S&P. 459–474. http://dx.doi.org/10.1109/SP.2014.36
[32] Yonatan Sompolinsky and Aviv Zohar. 2015. Secure high-rate transaction processing in Bitcoin. Financial Cryptography and Data Security (2015). http://doi.org/10.1007/978-3-662-47854-7_32
[33] Yonatan Sompolinsky and Aviv Zohar. 2016. Bitcoin’s Security Model Revisited. https://arxiv.org/abs/1605.09193. (May 2016).
[34] F. Tschorsch and B. Scheuermann. 2016. Bitcoin and Beyond: A Technical Survey on Decentralized Digital Currencies. IEEE Communications Surveys Tutorials PP, 99 (2016), 1–1. https://doi.org/10.1109/COMST. 2016.2535718
[35] Marko Vukolić. 2015. The quest for scalable blockchain fabric: Proof-ofwork vs. BFT replication. In International Workshop on Open Problems in Network Security. Springer, 112–125.
submitted by dj-gutz to myrXiv [link] [comments]

Forkology 301: The Three Tiers of Investor Control over Bitcoin

DanielKrawisz's article Who Controls Bitcoin is a must-read for anyone wanting to understand how Bitcoin is governed.
This post builds on Krawisz's point - that investors hold all the cards - by describing in more detail how Bitcoin investors can exercise their control over Bitcoin through a tiered or layered structure of increasing directness and radicalness.
Tier 1: Expression of Intent
Investors simply make it known, in a credible way, that they support some change (say a bigger blocksize cap), meaning they intend to buy more BTC if the change is made in good time, and sell BTC if it is not. Then there are three ways the ecosystem can react:
(i) Core Capitulates: The Core dev team is pressured to up the blocksize cap in Core and does so in a way that satisfies investors.
(ii) Competing Implementations Arise: If Core refuses or raises the cap too slowly, other implementations like BitcoinXT spring up and miners - enticed by the additional gains through a higher BTC price - adopt it.
(iii) Bitcoin Unlimited Renders the Previous Two Moot: Bitcoin Unlimited is another implementation in development that attempts to dispense with centralized blocksize planning entirely by allowing each user to set their own blocksize cap through a pulldown menu. Set the cap too low and your node might fail to track consensus as larger blocks get into the chain; set it too high and you might waste resources dealing with blocks that will end up orphaned. Users can also set a block depth after which they will accept a block higher than their set limit only if the block gets deep enough in the chain.
This mechanism constitutes a kind of built in fork-tolerant logic.
Instead of a preset group of developers opining over the "correct" blocksize cap or an ivory-tower scheme of centrally planned "Flexcaps," the blocksize limit is an emergent property of each individual node and miner's cost/benefit analysis and priorities for their own situation, much like the price of graphite. The concept of consensus becomes more fluid, with nodes sometimes objecting to bigger blocks by refusing to relay them, thereby assuming a risk of temporarily falling out of consensus. Somewhat like the English language, consensus on the rules is emergent rather than consensus rules being handed down from Core dev.
Instead of "Concur with Core or go pound sand," Bitcoin Unlimited's consensus on blocksize is an aggregate product of each node and miner positioning themselves favorably in the market due to their own calculations of the trade-offs for their unique circumstances.
The result is expected to be a soft blocksize limit that grows dynamically as market forces (orphan rates and other incentives), transaction demand, and technology levels change, in a way that maximizes investor satisfaction and therefore BTC price and miner revenue. Miners will up the size of the blocks they mine as transaction demand grows, and as long as they do so conservatively other miners and nodes (all interested in seeing the BTC price rise) will approvingly build on and propagate these blocks. Blocks over the soft limit will be discouraged by most nodes (by definition of the term "soft limit"), but if they manage to get several blocks deep into the chain most nodes will accept them. Miners a take a risk (orphan risk) in producing these slightly oversized blocks, edging forward carefully when they believe nodes will respond approvingly because investors and users are demanding it.
If Bitcoin Unlimited catches on, Core and XT's centralized blocksize plans become relics. Investors announce their intent, ideally through a prediction market or futures market but cruder measures would also have an effect, and miners react (conservatively!) through adjusting blocksize cap (and chain depth at which they'll give in and accept an oversized block) through the pulldown menu to rake in those juicy profits. Nodes also have a voice in what they help propagate, with an interest to aid bigger blocks because of their stake in the BTC price as business owners, holders, etc.
Tier 2: Fork Arbitrage on Exchanges
This case is more radical, but it is only required if a change is too controversial for something like XT's 75% threshold to be relied upon. Here, several weeks/months before the fork is to occur, Bitcoin exchanges prepare futures contracts for, say, coins in Core and coins in XT, and let investors effectively sell their coins in Core to buy more coins in XT, or vice versa.
For example if you have 10 BTC, you would of course have 10 Core bitcoins and 10 XT bitcoins after the fork if you took no action, but if you choose to participate in the arbitrage you might sell your 10 future Core bitcoins and use them to increase your future XT bitcoin count to 15 or 20 BTC. Why would it ever be only 15 BTC? This would be the case where you entered the arbitraging late and Core bitcoin futures had already fallen to half the price of XT bitcoin futures, meaning your 10 Core BTC only buys you 5 XT BTC. [For more technical details, see Meni Rosenfeld's How I learned to stop worrying and love the fork, though he doesn't address the futures contract innovation, which further streamlines the process by giving a very strong indication of the winner before the fork even happens.]
In almost all conceivable cases a definitive winner emerges (and if not, no other method is going to do any better at determining the winner), and the other fork either dies or becomes a niche alt-protocol coin (not really an "altcoin," since it shares Bitcoin's ledger). The niche coin would likely only arise and persist if there truly were a key tradeoff being made, as some small block adherents argue. In any case, hodler purchasing power is completely preserved by default if they choose not to bet in the "forkbitrage" process, even in the event of a persistent split.
This forkbitrage process represents a more direct expression of investor will than in Tier 1. (Also, it may be possible that this process starting up would kick off Tier 1 effects that would allow the more radical measure of forbitrage to be halted early, with the exchanges returning investors' bets.)
Tier 3: Spinoff with New Hashing Algorithm
This is the most radical, because it is only required in the scenario where "miners go insane" and do something ridiculous like upping the block reward or refusing to implement obvious necessary changes like blocksize cap increases, despite investor support, and where the miners would threaten to 51% attack the investors' chosen fork in the above forkbitrage process. Of course this can only be a short term threat, since the fork winning the Tier 2 forkbitrage process would soon have far more hashpower thanks to far greater market cap, but short term matters when you could be 51% attacked.
Here the Bitcoin ledger is copied over to the investors' chosen protocol, so that all holders have the same number of coins (and same percentage of all outstanding coins) in the "new" coin, say a larger blocksize cap coin. The World Wide Ledger is preserved, which is all that should matter to investors, and the "old" Bitcoin is again sold off to nothing or goes niche. Hodler purchasing power is preserved, of course.
This is the very purest expression of investor will. Miners can be called a kind of investor, but with some complications. Spinoffs allow investors to circumvent even the miners - a radical measure for outlandish scenarios.
Tier 1 lets investors deal with attempted developer control, Tier 2 lets investors deal with controversy, and Tier 3 lets investors deal with pervasive miner irrationality. This is how investors rule the roost.

Previous Forkology posts and discussions:
Forkology 101
Forkology 201 (guest post by Peter__R)
submitted by ForkiusMaximus to btc [link] [comments]

Why do I believe it was BCN destiny to be born in 2012?

Why do I believe it was BCN destiny to be born in 2012? Just look at this and see yourself:
1983 - Blind signatures were invented by David Chaum link 1997 - HashCash (proof of work system) was invented by Adam Back link
2001 - Ring signatures were invented by Ron Rivest, Adi Shamir, and Yael Tauman link
2003 - Mart n Abadi, Michael Burrows, and Ted Wobber presented "Moderately hard, memory-bound functions"link
2004 - Patrick P. Tsang and Victor K. Wei presented their paper "Short linkable ring signatures for e-voting, e-cash and attestation" link
2005 - Matthew Franklin and Haibin Zhang with "Unique Group Signatures" study link
2005 - Exponential memory-bound functions for proof of work protocols by Fabien Coelho link +2006 - "Traceable Ring Signature" by Fujisaki and Suzuki link
2008 - Bitcoin whitepaper by Satoshi Nakamoto link
2009 - Stronger key derivation via sequential memory-hard functions by Colin Percival link
2009 - First Bitcoin block was generated
2010 -2012 - Bitcoin Anonymity Problem Discussions link
2011 - An Analysis of Anonymity in the Bitcoin System, Fergal Reid and Martin Harrigwere link
5/15/2012 - Dorit Ron and Adi Shamir made Quantitative Analysis of the Full Bitcoin Transaction Graph link
6/8/2012 - Bytecoin Wiki started link
6/30/2012 - Bytecoin launch announcement link- first news
7/4/2012 - First BCN block was generated link
8/6/2012 - Destination Address Anonymization in Bitcoin (one-time addresses in BCN) link
10/19/2012 - Evaluating User Privacy in Bitcoin by Elli Androulaki, Ghassan O. Karame, Marc Roeschlin, Tobias Scherer, Srdjan Capkun. link
12/12/2012 -CryptoNote whitepaper v 1.0 link
12/13/2012 - Analysis of hashrate-based double-spending, Meni Rosenfeld link
10/17/2013 - CryptoNote whitepaper v 2.0 link
Here we see how the technology logically came to the advent of cryptocurrencies with ring signature and memory-bound function PoW implementation. Soon after Bitcoin's release the community started to raise concerns about its anonymity with multiple solutions and propositions. High concentration of theoretical papers on these topics in 2009-2011 most probably spurred the brightest minds to make attempts of practical e-cash with ring signatures realization. Therefore, BCN couldn't but appear in 2012.
Based on https://bitcointalk.org/index.php?topic=512747.msg7093354#msg7093354
submitted by joethejudge77 to BytecoinBCN [link] [comments]

Israel Bans Crypto Companies from the Tel Aviv Stock Exchange

The Tel Aviv Stock Exchange or TASE, has announced that crypto based companies are banned from the market indices. The regulation has been instituted by the Israel Securities Authority (ISA) after the authority had announced their plan for regulating cryptocurrencies in the TASE market earlier this year.
An ICO regulations and guided working manual is to be published soon this year and according to the ISA, the change of TASE regulations has no association with this new crypto update. The committee has instead issued a cautionary statement about investing and trading in cryptocurrency. ISA claims, “Such investment incurs many exceptional risks, including an absence of liquidity and ability to convert the currencies to money, exceptional price volatility, illegal activity, and risk of fraud”.
The warning from ISA further states that investor must be be prepared to face the high probability of risk from investing money, directly or indirectly, in cryptocurrency or crypto company. They elaborate on the risks of losing money and assets when it comes to the crypto market and trading in cryptocurrency as well. Many banks like the Bank of Israel, do not categorise cryptocurrency like Bitcoin as a valid type of currency but rather as an asset.
Anat Guetta, the chair of ISA, has held the post from January this year and has already taken her stance on cryptocurrency. She states that barring crypto companies from TASE will safeguard the market against passive investors that are prone to such risks. She further warns of the volatile environment surrounding crypto investment and high risk of losing money in this market. As per the new regulation, the ISA will review the regulations in TASE and block out any company related to cryptocurrency. This means that any business, exchange, platform, or company that allows investing, trading, and mining of crypto coins like Bitcoin, Ether, and other Altcoins will be restricted from investing in TASE. This regulation is temporary for the length of this year, until it is reviewed again and reinstated or not based on the market projections and developments. Chairman of the Israel Bitcoin Association, Meni Rosenfeld, responded to the new regulations on cryptocurrency, by stating, “There are indeed several risks in investing in digital currencies, and people should take them into account in order to make wise decisions. Investing in this sector is not suitable for everyone; it is only for those who understand both the potential and the risks”.
submitted by moneytradecoin to u/moneytradecoin [link] [comments]

the first stop of Bitbank business trip plan in Israel

Bitbank business trip plan First Stop The development of bitcoin around the world is increasing at a rapid pace and each country will use bitcoin in its own unique way. Bitbank is dedicated to being an active contributor to the global bitcoin community by partnering with and supporting organizations and individuals who are leading the way in blazing the trail for the Internet of Money. During the next few months Bitbank will be visiting several countries to learn about the bitcoin scene in each location to share how people are using this groundbreaking technology to transform money, business, government and society. Stay tuned for regular updates and news at Bitbank.com and follow us on Facebook, twitter, wechat and weibo. Our first stop is the technological mecca of the Middle East Israel. Israel is home to one of the highest concentrations of Bitcoin developers in the world with one of the most active and organized Bitcoin communities in the world. Our fist stop was the Bitcoin Embassy in the beautiful city of Tel Aviv, the embassy is located accross the street from the Tel Aviv stock exchange (A sign of things to come we think). It is full of information about bitcoin, bitcoin tshirts and merchandise. It is a must see for any bitcoin fan! There we had the chance to speak with community members including the founder of the embassy Meni Rosenfeld. Meni is a well known voice in the global bitcoin community, he has also been the main voice for Bitcoin advocacy in Israel organizing the first meetup in the country which has grown from 3 people in the beginning to over 1000 members today. We also had the pleasure to meet some of the other members of the community, who were very friendly and happy to share the news and help us learn about the development of Bitcoin in Israel. Including Nadav, the creator of Bitrated a peer to peer e-commerce platform that allows for near trustless transactions around the world. Jonathan the CEO of Bits of gold Israels leading Bitcoin exchange, and Nimrod CEO of Simplex whos company helps to make it easy for people to use their union pay and credit cards at bitcoin exchanges and websites. The development of Bitcoin in Israel is driven by the passion and amazing technical prowess of its community. Traditional media and finance are taking a closer look at the benefits of bitcoin and how Israel can be one of the leaders in this game changing technology. Bitbank would like to send a big thank you to the community in Israel for the warm welcome we received and look forward to seeing what comes next from this vibrant community in the future.
submitted by bitcoin_andylee to Bitcoin [link] [comments]

05-25 05:26 - 'the first stop of Bitbank business trip plan in Israel' (self.Bitcoin) by /u/bitcoin_andylee removed from /r/Bitcoin within 107-112min

'''
Bitbank business trip plan First Stop The development of bitcoin around the world is increasing at a rapid pace and each country will use bitcoin in its own unique way. Bitbank is dedicated to being an active contributor to the global bitcoin community by partnering with and supporting organizations and individuals who are leading the way in blazing the trail for the Internet of Money. During the next few months Bitbank will be visiting several countries to learn about the bitcoin scene in each location to share how people are using this groundbreaking technology to transform money, business, government and society. Stay tuned for regular updates and news at Bitbank.com and follow us on Facebook, twitter, wechat and weibo. Our first stop is the technological mecca of the Middle East Israel. Israel is home to one of the highest concentrations of Bitcoin developers in the world with one of the most active and organized Bitcoin communities in the world. Our fist stop was the Bitcoin Embassy in the beautiful city of Tel Aviv, the embassy is located accross the street from the Tel Aviv stock exchange (A sign of things to come we think). It is full of information about bitcoin, bitcoin tshirts and merchandise. It is a must see for any bitcoin fan! There we had the chance to speak with community members including the founder of the embassy Meni Rosenfeld. Meni is a well known voice in the global bitcoin community, he has also been the main voice for Bitcoin advocacy in Israel organizing the first meetup in the country which has grown from 3 people in the beginning to over 1000 members today. We also had the pleasure to meet some of the other members of the community, who were very friendly and happy to share the news and help us learn about the development of Bitcoin in Israel. Including Nadav, the creator of Bitrated a peer to peer e-commerce platform that allows for near trustless transactions around the world. Jonathan the CEO of Bits of gold Israels leading Bitcoin exchange, and Nimrod CEO of Simplex whos company helps to make it easy for people to use their union pay and credit cards at bitcoin exchanges and websites. The development of Bitcoin in Israel is driven by the passion and amazing technical prowess of its community. Traditional media and finance are taking a closer look at the benefits of bitcoin and how Israel can be one of the leaders in this game changing technology. Bitbank would like to send a big thank you to the community in Israel for the warm welcome we received and look forward to seeing what comes next from this vibrant community in the future.
'''
the first stop of Bitbank business trip plan in Israel
Go1dfish undelete link
unreddit undelete link
Author: bitcoin_andylee
submitted by removalbot to removalbot [link] [comments]

Decred - An Overview

Decred is an open, progressive, and self-funding cryptocurrency with a system of community-based governance integrated into its blockchain. At its core is a hybridized proof-of-work proof-of-stake (PoW/PoS) consensus system that aims to strike a balance between PoW miners and PoS voters to create a more robust notion of consensus. The project is a result of the theoretical proposals brought by proof-of-activity (PoA) and MC2 in 2013. Decred development started in April, 2014 with a single developer and expanded to include developers from btcsuite shortly thereafter.
Decred is built in the spirit of open participation and we have provided below a full disclosure of the technical features of the system, wallets and mining, initial funding and distribution, project governance and development, and a group contribution timeline. We hope to launch mainnet on January 18th, 2016, and will provide additional details in this thread. Everyone is welcome to participate, and you are certainly welcome to join the development and project groups if you have interest in contributing to our efforts!
i. Technical Features
The features below are implemented in Decred and will be available in full at launch. For a deeper description, please consult the Decred Technical Brief (DTB001).
•Novel hybridized proof-of-work/proof-of-stake (PoW/PoS) consensus system - A decentralized lottery is used to select PoS miners to vote on PoW blocks. The PoW and PoS subsidies account for 60% and 30% of each total block subsidy, respectively. This system is based on that of MC2, which is very similar to, but developed independently from, Proof-of-Activity (PoA) by Iddo Bentov, Charles Lee, Alex Mizrahi and Meni Rosenfeld. •Cold staking and decentralized stake pooling - The ability to generate new coins without the risk of having your coins online when PoS mining. The PoS mining system has also been engineered with distributed, decentralized stake pooling in mind, so that even those with small amounts of stake can participate in network validation. •Internal voting system for the addition of new features and hard or soft fork selection - Both PoW and PoS miners can vote for features and issues through bit flags, providing a sensible mechanism for resolving disputes about the features of the blockchain. •Immutable transaction hashes ("transaction IDs") by separating transaction signatures from the rest of the transaction data - A permanent fix for transaction hash malleability has been implemented that prevents mutability of the transaction hash by separating it from its input signatures. This allows more efficient SPV validation. Fraud proofs have also been added. •Elliptic curve cryptography over secp256k1 with optional Curve25519 support - The Bitcoin scripting system has been modified to allow for simple, drop-in addition of new elliptical curve digital signature algorithms. •Schnorr signatures with threshold n-of-n support - In addition to supporting Schnorr signatures, groups of signers can now jointly sign transactions off-chain in constant size signatures, ensuring higher privacy and less blockchain bloat. •Script enhancements and new OP codes - New OP codes have been added to the existing Bitcoin scripting engine, and extensions for the plug-in use of future scripting engines have been added. •PoW mining using BLAKE256 hash algorithm - Inspired by Bernstein's Chacha stream cipher, SHA3 finalist BLAKE256 offers speed as well as high security. •Compatibility with Bitcoin transaction scripting system - Decred's scripting system has been derived from Bitcoin's with care in ensuring that all future updates to the Bitcoin transaction script will be easily extensible to Decred. Further, any newly created functionalities will also be devised with backwards compatibility with Bitcoin in mind. •Modularized, easy-to-use Golang btcsuite codebase - Thanks the to the codebase inherited from btcsuite, adding new features to the daemon or wallet will be facile. Decred will episodically sync updates from btcsuite, so that it benefits from the latest developments in Bitcoin. •Hierarchical deterministic (HD) wallets - Wallets use a seed to deterministically generate addresses, so your wallet can be restored from a single BIP0032 seed. •Transaction expiration - Transactions have a new expiration field to prevent inclusion into the blockchain after a certain height. •Patches for intrinsic Bitcoin bugs - Extra push for multisignature scripts has been removed, SIGHASH_SINGLE behavior has been corrected. •Approximately 21 million coins - Exponential decay in subsidy or the number of coins generated per year. •Self-funded development via block subsidy - In order to have an ongoing source of funding for development work, a consensus rule has been added to allocate 10% of each block subsidy to a development organization. This entity is transparent and responsible for funding development work performed by current and new developers so that the project remains sustainable without a funding dependence on outside forces in the future. Decred therefore improves with growth in a sustainable way and is accountable only to its users.
ii. Wallets and Mining
•Web wallet service - In order for users to have access to a GUI on all platforms, we have created a web wallet service forked from BitPay's Copay wallet and its dependencies. This wallet allows users to access all the basics with Decred: sending and receiving coins, multisig transactions. •Command-line wallet - For more advanced users, we have a command-line wallet, dcrwallet. dcrwallet allows users to mine PoS and collect rewards by participating in the PoW/PoS consensus system. •Simple GPU miner - A simple AMD GPU miner that connects to a local daemon will be available before launch. In the future, proper getblocktemplate functionality will be enabled and pool software will be made available.
iii. Initial Funding and Airdrop
Decred opted for a different funding model in an attempt to shift the risk carried by supporters to the developers of the project. Instead of asking interested parties to fund the development of the software, the developers decided to pool funds together and carry the project to completion before making it public. The consensus was that this is an ethical path given the realities of funding software development, due to the fact that the developers alone carry the risk of the project failing, whereas in the past potential users were expected to pay for coins before any code was written. We felt this was unjust.
The development of Decred was funded by Company 0 and from the pockets of its developers individually. The cost of developing the project, in terms of developer pay, totals to approximately USD 250,000, which Company 0 paid to developers. An additional amount of approximately USD 165,000 has been allocated for unpaid work and individual purchases by developers. We felt that the most equitable way to handle compensation for these expenses was to perform a small premine as part of the project launch. The model is unusual in that no developer received any amount of coins for free - all coins owned by developers will either be purchased at a rate of USD 0.49 per coin from their own pockets or exchanged for work performed at the same rate.
The premine consists of 8% of the total supply of 21 million coins, meaning the premine consists of 1.68 million coins. Rather than allocating the entire premine to the bring-up costs, we decided to split the premine equally between compensation for bring-up and an "airdrop", where we freely give an equal amount of coins to a number of airdrop participants. This means Company 0 and its developers will have put roughly USD 415,000 into the bring-up since April, 2014 and receive 4% of the total supply, 840,000 coins (at USD 0.49 per coin). The remaining 4% will be spread evenly across a list of airdrop participants as part of an effort to build the Decred network and decentralize its distribution. Coins held by Company 0 will be used to fund its ongoing work on open-source projects, such as Decred and btcsuite.
Giving away these coins in an airdrop allows us to accomplish several things at once for the project: enlarge the Decred network, further help decentralize the distribution of coins, and allow us to get coins into the hands of people who are interested in participating in the project. Decred is fundamentally about technological progress, so the airdrop will target individuals that have made contributions to advance technology in its various forms. The maximum number of airdrop participants is capped at 5,000 individuals, so we recommend registering sooner rather than later. These coins will be given away unconditionally and there is zero expectation of Decred receiving anything from you in return for these coins.
Sign up for the airdrop is currently open, but the airdrop registration will commence on January 4th, 2016. People who have been selected to participate in the airdrop will receive an email that contains a link to a web registration form. This form will require airdrop participants to enter an address to which their coins can be sent. Binaries and source code will be made available so that you can generate a wallet seed and an address for your airdrop coins. Once you have entered your receiving address into the airdrop webform and submitted it, you will receive your coins on the projected launch date of January, 18th, 2016.
iv. Project Governance and Development
In addition to the technical features that make up the technology, Decred as a project introduces several development and governance features and proposals to ensure and steer long-term growth. We encourage participants to discuss these topics earnestly, as we want to ensure the system of development and governance is built on a solid foundation.
•A multi-stakeholder development ecosystem that welcomes and empowers participants who want to build new functionality and improve on existing features. •Any party can submit feature proposals and developers are paid for work to fulfill requirements. This is done in full view of the community in a system designed to fight against ingroup-outgroup dynamics. •The initial contributors are the developers responsible for btcsuite (est. early 2013 - present). •A proposal for a layered form of transparent meritocratic governance that extends beyond proof-of-work and proof-of-stake mechanisms to bring forward and represent insider and outsider voices in the community. •A proposal for bottom-up decision-making through the Decred Assembly, an evolving and inclusive list of community members who make non-financial contributions to the project through their work and effort. •The project is bound by the Decred Constitution on the core principles of finite issuance, privacy, security, fungibility, inclusivity, and progressive development of the technology that keeps these principles together.
v. Group Contribution Timeline
Below are key points of free and open-source contributions made by the Decred developers to the digital currency ecosystem since 2013. The largest of which is the btcsuite package, which comprises a suite of packages and tools for working with Bitcoin in Golang, and includes btcd, a full node, mining capable, Bitcoin implementation. To date, the total contribution across btcsuite represents 98,046 lines of code, 44,576 of which are test coverage.
vi. Additional Information
Website: https://decred.org Forum: https://forum.decred.org Wiki: https://wiki.decred.org Reddit: https://reddit.com/decred Twitter: https://twitter.com/decredproject IRC: #decred on irc.freenode.net
submitted by ocnios to decred [link] [comments]

Most alt-coins are NOT secure enough, they exist only for entertainment and speculation (Taken from /r/Bitcoin)

TL;DR IMO this guy hates alt-coins.
OP: http://www.reddit.com/Bitcoin/comments/22aw8c/most_altcoins_are_not_secure_enough_they_exist/
(I believe this needs to be posted to /bitcoin[1] as Bitcoin users/enthusiasts need to know the difference between Bitcoin and other cryptocurrencies. About author: I'm subscribed to /bitcoin[2] since 2011, and have been involved in cryptocurrency security research for several years.)
Let's talk about security aspect of cryptocurrencies. I'm afraid an average user knows very little about this topic: he might know that hashrate is needed to protect the blockchain, and that higher hashrate is better, as it implies that attacker needs to spend more to get control of the blockchain.
But there is a plenty of other kinds of attacks (or, rather, economic models of attacks), some of which have much higher practical significance.
Let's start with something simple: there is a straightforward and rigorous model of double-spending attack under condition that attacker has a fraction of total network's hashrate. I highly recommend Meni Rosenfeld's Analysis of hashrate-based double-spending paper (PDF[3] ).
The main takeaway from this paper is that "maximal safe transaction value" is directly proportional to block reward (i.e. amount of coins miners get for each block). It is easy to understand this intuitively: bigger reward means that miners get more money from normal mining, so they will be reluctant to try double-spending attacks. On the other hand, if block reward was negligible, double-spending could be a lucrative source of revenue.
Let's look at numbers: if attacker controls 26% of hashrate and number of confirmations is 6, maximal safe transaction value is 1113 BTC when block reward is 25 BTC. This is pretty cool: you only need to wait 1 hour to make sure you irreversibly received half million USD worth of bitcoins (I assume exchange rate of $450 (Ɖ960k) for 1 Bitcoin).
However, situation is pretty different for alt-coins which have much less valuable block rewards. For example, imagine there is a Foocoin with exchange rate of $1 (Ɖ2.1k) for 1 Foocoin. If Foocoin's block reward is also 25 foocoins, then max save transaction value for 6 confirmations is only $1113 (Ɖ2.4M) USD worth of Foocoins. It doesn't look like Foocoin is suitable for commerce, does it? One could say that Foocoin simply requires larger number of confirmations for larger transactions. But that's wrong: higher number of confirmations helps only under condition that attacker is unable to obtain more than 50% of total hashrate, but for most alt-coins it isn't true.
First of all, let's note that so-called miners simply rent their equipment to "mining pool operators" and are paid in crypto-currency for it. In many cases they don't even care what cryptocurrency they mine as long as they are being paid. See Middlecoin[4] : This pool automatically mines the most profitable scrypt coin, automatically exchanges those coins for bitcoins, and pays out entirely in bitcoins.
So, miners who mine using Middlecoin do not know if their equipment is being used to mine Litecoins or Dogecoins or something else. And they wouldn't care if it is used for attacks on alt-coins, as they are being paid in bitcoins. Let's consider a scenario where Middlecoin-like pool has higher hashrate than Foocoin, e.g. Middlecoin (not Middlecoin specifically, but any pool like that) has 20 GH/s, while Foocoin has 10 GH/s. Here's how one can profit from it:
  1. Buy $1M worth of Foocoins, get them into your wallet.
  2. Make an agreement with Middlecoin: you rent they hashrate for a couple of hours, paying them in bitcoin, slightly above what most profitable alt-coin yields.
  3. Send your foocoins to exchange Bar.
  4. Start mining a private chain which has a double-spend transaction which sends coins to exchange Baz.
  5. After your transaction gets 10 confirmations on the normal chain, convert foocoins to bitcoins on Bar and withdraw them immediately.
  6. After withdrawal transaction is confirmed on Bitcoin network (and thus cannot be reversed), you release the private chain you have mined, causing reorganization. You should have mined 20 blocks by then under if Middlecoin has hashrate which is twice higher than normal Foocoin's hashrate.
  7. Your deposit to exchange Baz is now confirmed, converl your foocoins to bitcoins again, and withdraw immediately. A day later 20 blocks you have mined will get mature, and you'll be able to sell them too.
If Foocoin price doesn't change in process, you can get approximately $1M profit on this attack, as cost of renting a mining pool is approximately equal to value of mined blocks.
In practice, you'll lose some money due to lack of liquidity on exchanges, so profit will be less than $1M.
The conclusion we get from this analysis is that alt-coins which have only a small fraction of total hashrate for a certain mining algorithm are extremely non-secure. And they cannot grow big: as soon as exchanges will have enough liquidity, it will be possible to perform the attack I described, which will result in the price drop.
So almost all alt-coins are simply not suitable for any kind of "real economy" applications. They are doomed to have high volatility, shallow markets, low "max safe transaction value".
One can't deny the fact that it is possible to make money on alt-coins. But that's just gambling. And people who create new alt-coins are in same position as people who build casinos. It is a business, but it is the entertainment sector, not in 'real economy' or 'financial' sectors as some people are trying to pretend.
Bitcoin is one of few cryptocurrencies which are actually serious. It isn't perfect, but attacking Bitcoin is very hard, so transactions worth millions of dollars can be confirmed in matter of hours. Same cannot be said about alt-coins, and this situation won't change unless new cryptocurrency designs will be found.
If there is an alt-coin which is more-or-less secure, it is probably Litecoin. Its hashrate is a significant fraction of total scrypt hashrate, so attacking Litecoin is hard. Interestingly, at some point Dogecoin's hashrate was higher than Litecoin's but it dropped after block reward have dropped. So, again, block reward is important for security.
This has dire implications for alt-coins which have short block reward schedules. If all coins will be mined in two years, this mean that alt-coin will be dead in two years.
(It's worth noting that same problem might affect Bitcoin in future, like in 10 years or so.) Now there is a question: Is there a way to make multiple currencies all of which will be secure? Probably. There are several approaches:
submitted by ijmolder93 to dogecoin [link] [comments]

- hack.ether.camp - Interview With Meni Rosenfeld LessWrong - Bitcoin, Chess AI and the Solstice (Hebrew, 19.12.2017) Meni Rosenfeld - Early Days of Bitcoin Mining EB49 – Meni Rosenfeld: Mining Pool Reward Systems, Bitcoin Economics, Bitcoin in Israel The Road To Bitcoin Adoption

Chủ Nhật, Tháng Chín 13, 2020 Liên Hệ (Advertising) Bitcoin là gì; Blockchain là gì; Tôi Yêu Bitcoin The theoretical background behind the idea was developed with the help of Meni Rosenfeld, an Israeli mathematician who has also been a main organizer of the Israeli Bitcoin community for the last two and a half years. The furthest developed implementation of the project today, Webcoinx, was written mostly by Ukrainian developer Alex Mizrahi, but was funded by eToro, a popular “social ... Meni Rosenfeld, the Chairman of the Israeli Bitcoin Association, told Cointelegraph that he believes 24-hour fees show too short a timeframe to be particularly significant. He pointed out that historic data shows that the Bitcoin transaction fee rate is more volatile than the asset’s price itself. Still, he noted that if the trend continued it would acquire more significance: “If the trend ... Meni Rosenfeld. Follow . Mar 13, 2018 · 18 min ... One of the first burning questions I had when I was first introduced to Bitcoin was how the whole thing was supposed to scale. Concepts I’ve ... Meni is the author of the “colored coins” concept and the Head of several IT startups. Nevertheless, public work is now his main activity. Meni Rosenfeld has been the undisputed leader of the Israeli Bitcoin Association (IBA) for almost five years now. He talked on the organization in detail in an interview with Bitcoin Magazine.

[index] [27596] [45888] [20787] [20120] [19655] [13530] [29932] [25795] [11602] [44685]

- hack.ether.camp - Interview With Meni Rosenfeld

1) If you enjoyed this, I'd welcome a tip here: 185By4a1Lt2HnKLAKR5EmidZMYgp5DDSaj 2) Mining Pool Reward Methods, lecture by: Meni Rosenfeld of Bitcoil.co.il... Follow this channel for in-depth live interviews with various influencers in Bitcoin, crypto & blockchain. Email me at [email protected] for any feedback, ... - hack.ether.camp - Interview With Meni Rosenfeld More information and registration as fan or a developer: https://hack.ether.camp Slack: http://www.ether.ca... Meni Rosenfeld is Founder of Bitcoil and Chairman of the Israeli Bitcoin Association. Having organized several meetups and conferences in Israel, he is a very active member of the Israeli Bitcoin ... The lecture took place in the Inside Bitcoins Tel Aviv 2014 conference, organized by the Israeli Bitcoin Association and Buzz Productions, on October 19-20, 2014. Slides (for the entire conference ...

#