Category Archives: Bitmain

Bitmain not Mining Bitcoin Cash Hints at Continued Support for SegWit2x

There are many things we can learn from the initial launch of Bitcoin Cash. First of all, a lot of people sold their coins too early and will regret that decision by now. Secondly, Bitmain has no plans to support BHC for the time being. Otherwise, they would have mined at leas tone network block, … Continue reading Bitmain not Mining Bitcoin Cash Hints at Continued Support for SegWit2x

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Why Bitcoin “drama” is not bad at all?

Why Bitcoin "drama" is not bad at all?

There are many reasons for such statement.

Satoshis vision based on several key fundamentals:

  • trustless
  • decentralised
  • distributed

If we take look at Bitcoin today I have question — what of above fundamentals he has today and there are few keywords:

  • AsicBoost
  • AntBleed
  • BitmainTech
  • Roger Ver, Jihan Wu, Gavin Andresen, Jeff Garzik, Barry Sielbert, etc

Bitcoin today can be anything except trustless, decentralised and distributed. Bitcoin today is BitmainTech Corporation! Large number of miners are in BitmainTech slavery so I do understand their position.

Core developers are tech people with honest thinking and boy scouts. Certain number of miners as well. Problem is that politics and greed entered Bitcoin and Crypto arena. Those without technical skills and vision "smell blood" and as sharks arrived in that arena. Bitcoin is gangrenous at the moment and gangrene must be removed. That means there will be pain but after that wound will heal. Or Bitcoin Community will be on it's knees and accept new China masters and their puppets…

There will be NO agreement with China Government, Jihan, Roger and company. They want it ALL. Profiling showed many times that with such mindset there is no agreement. I wrote about it few months ago so if interested check it out.

To make it clear, if Segwit NOT activated by August 1st long war is ON. If Core kneels down — Bitcoin as Satoshi vision is LOST. This will be war between Bitmain Miners and Bitmain Satellite companies on one side and Knowledge (Core Developers) and Awaken Users on other side. Outcome is certain but it will take time and bring pain.

Luckily Crypto Ecosystem is today mature enough to take hit like that and it is not gloom and doom all the way.

When we speak about Crypto Ecosystem he must as well be distributed and decentralised. Question is should whole new dimension in human evolution be dependant on only one "product" — Bitcoin. Many will argue that Alts are centralised. Most of them are. But, at the moment, most centralised is Bitcoin and this "drama" is raging because of "Shadow Mining" BitmainTech centralisation and by GeoLocation centralisation is in China.

As well, people who claim that "Alts are centralised" probably heard that on Internet or social networks. If you look closely there is certain number of Alts that are decentralised, trustless and distributed much, much more than Bitcoin. People mostly do not investigate themselves but rather blindly join "camps"….

At the time of writing this text I see that some Alt's bottomed VS Bitcoin and expect them to reverse in correlation soon. Solid, robust, prosperous Crypto World should not be dependant on only one coin even if that is Bitcoin. I wrote about that as well so check if you will.

I am over 20 years on market and I am covered with scar's. But I did learn few rules in that time:

  • Never marry investment — investment is bitch,
  • Do not let politics in portfolio,
  • "Be right and seat tight" — by Jesse Livermore
  • Wealth is made when there are rivers of blood — not when markets go up
  • Never chase rabbit
  • Turtle will win the race not rabbit
  • Good investor must always be ready for U-turn if fundamentals/environment change

I did prepare for this 5 months ago. When there was full blown bull I put some profit in metals. Have solid revenue stream through several vectors so cash was not needed. But I did significantly reshape Crypto portfolio. I do not want to get Goxed. Skipped that first time and learned a lot.

What I learned in this Bitcoin "drama" is that whole Crypto World is currently hostage of Bitcoin. Bitcoin is hostage of China Government hijack attempt through BitmainTech Asic dependant miners. To resolve this it will take time.

I am confident that this environment is WIN-WIN for some Alt's:

  • if drama resolved everything will skyrocket — Alt's for sure more than Bitcoin — especially some Alt's
  • if drama escalates I am 100% sure that some Alt's will soon have reversal correlation with Bitcoin. Drop VS Bitcoin has already stopped. I am sure that Crypto World will NOT die whatever happens to Bitcoin as well.
  • I am sure that at the and Bitcoin will have to get rid of above mentioned gangrene and prosper — will take time, will be painful but at the end all this is Bitcoin feature NOT bug. But was made when community left all power in miners hands forgetting that miners are people only and greed will be there as well.

I am looking for fundamentally good Alt's that are distributed, decentralised, immutable, trustless. They must NOT be/have:

  • P0W only
  • China crew/dev majority
  • over 200 mil coin cap
  • located mostly in China — must be distributed world wide (MN/P0S helps here)
  • Cult person as dev leader or have centralised dev team

They must HAVE:

  • they must generate "fixed" income through MN/P0S/DPoS — trust me it is much easier to look price drop when your amount of coins is growing and you do nothing but stake. When prices go up again you get surprised every time…

Yes, there are investments like that. No, I am not going to shill them here.

If interested — go find them yourself….. ;-)

Conclusion is that Bitcoin will have to grow up and mature as well as whole Crypto World.

All of us will have to learn few things in this new dimension.

Only 1% will make real wealth here and those will be ones that go against heard and sound delusional to most of you.

Time will do the rest…

Good luck and God bless….

Bitcoin’s Price Recovers Post $500 Crash, Block Size Debate Heats Up

Two days ago on June 12th, Bitcoin’s price crashed $500 from a high of $2980 to a low of $2480 on Bitstamp. Since then, the price climbed over 10% and is trading at $2754 at the time of writing. This article will go over potential factors that might have caused the crash, and try to explain Bitcoin’s recent recovery.

As discussed in our previous article regarding the crash, OkCoin’s liquidation of long positions was the catalyst for the panic sell. As the contracts executed, they created massive sell pressure on the market. Combine that with Bitcoin’s price trading in uncharted territory and you get a 17% drop in 12 hours.

On the upside, Bitcoin’s price has recovered over 10% since then. The $2700 level has been serving as solid support for the past 24 hours as the market is deciding its next move.

Taking a look on Tradingview, it looks like many traders believe now is a good time to short Bitcoin. For example, DLavrov from Tradingview suggests that Bitcoin’s price may drop to around $2500 according to Ichimoku signals. Those are technical indicators which help define support and resistance zones based on moving averages. He provides the following chart explaining his reasoning:

ichimoku signals

Chart: Tradingview

“We can trade Bitcoin based on Ichimoku signals. Price reverses from the kumo (clouds) and RSI confirms it. DMI shows trend market conditions and allows trading. Entry level for short trades can be below 2680.00 with stop above 2800 level. Profit target is near 2500 level.” –@LavrovFx

For those of you who are unfamiliar with a DMI (Directional Movement Index). Its purposes is to define whether or not a trend is present. Looking at the above chart’s DMI, we can see that the ADX (blue) was high, signaling that a trend was forming. However, looking at a more updated chart we can see that the DMI has retracted significantly, meaning the potential for a downtrend isn’t as high as before.

On the upside, ew-forecast suggests that Bitcoin is trading in its final Elliot wave, and that the price will see much more highs. He presents the following chart for his Bitcoin price movement prediction:

bitcoin price elliot waves

Chart: Tradingview

Bitcoin is unfolding an impulsive pattern to the upside, which means that red wave 4 correction has ended around the 1800 mark. We now see a five wave impulsive movement which unfolded in black wave 3 and found a top near the 3000 level. Wave 3 can also be completed and recent pullback could represent black wave 4 correction. That said, if wave 4 correction is completed then we can expect a new recovery to follow into the final black wave 5.” –@ewforecast

Block Size Debate Heats Up

Moving away from technical predictions, and switching our focus to upcoming events that might influence Bitcoin’s price, the block size debate is getting heated once again. Recently, mining giant Bitmain released a blog post describing their contingency plan for the UASF aka BIP148. Bitmain will ultimately mine their own fork of Bitcoin once UASF activates on Aug. 1st. Reddit user theflar summarized the announcement best: “It’s cartoon-level supervillainery.”

One can only speculate about how these news may affect Bitcoin’s price in the coming days. One thing is for certain, Bitmain hard forking away from core shows that miners are still not in agreement with the rest of the Bitcoin user base. This announcement definitely puts meaning to “Fork your mother if you want to Fork.”

Disclaimer: This is not trading advice. If you liked this article, follow us on Twitter @themerklenews and make sure to subscribe to our newsletter to receive the latest bitcoin, cryptocurrency, and technology news.

Eric Lombrozo Issues A Stong Warning to Bitmain To “Get With The Program”

It is evident there are quite a few different opinions on the future of Bitcoin. Eric Lombrozo recently issued some very strong comments regarding this situation. In fact, he feels Bitmain needs to “fall in line” regarding the scaling of Bitcoin. A very interesting tweet, although it will undoubtedly unleash a flurry of insults among … Continue reading Eric Lombrozo Issues A Stong Warning to Bitmain To “Get With The Program”

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BitPay Enters Agreement with Bitmain to Develop Open Source Blockchain Security Software

ATLANTA — MAY 2, 2017 — Today bitcoin payments leader BitPay announced that it has entered into a multi-million dollar development agreement with Bitmain Technologies, the foremost provider of the “mining” hardware used to secure blockchains. Over the course of its multi-year agreement with new customer Bitmain, BitPay will create advanced open source software for the miners, mining pools and full node operators which maintain and secure blockchain transactions.

BitPay will draw on its more than six years of experience in building payment technology and secure open source platforms for payments on the Bitcoin blockchain. BitPay has a long tradition of servicing the most significant companies in blockchain mining hardware and is now pleased to count Bitmain among its customers. BitPay also processes hundreds of millions of dollars in payments yearly for businesses worldwide, including industry leaders like Microsoft, Valve, and PaySafe.

“At BitPay, we recognize that there is an untapped market of mining companies that require more advanced platforms for their businesses than are available today,” said BitPay CEO Stephen Pair. “We value having Bitmain as a customer, and we believe that miners and mining technology providers like Bitmain play a vital role in the security and ongoing success of the Bitcoin blockchain.”

Bitmain is one of the most successful providers of the hardware used to secure blockchain transactions. In recent years, the company has played a major role in hardware innovation to support the exponential growth of Bitcoin — the world’s first and most successful blockchain.

“BitPay has established itself as a leader in open source development for the Bitcoin blockchain,” said Bitmain CEO Jihan Wu. “We believe that together we can make real improvements in how we secure blockchain transactions and grow the impact of blockchain technology in digital payments.”

About BitPay

Founded in 2011, BitPay is the first and most experienced provider of blockchain payment technology. The company provides innovative tools for digital payments in ecommerce, business to business, and supply chain transactions, serving industry leaders like Microsoft, Valve, and PaySafe.

BitPay has offices in North America, Europe, and South America and has raised over $32 million from top investors including Index Ventures, Peter Thiel’s Founders Fund, and Sir Richard Branson. For more information on BitPay and what it’s doing in the world of payments, visit www.bitpay.com or email media@bitpay.com.

About BitMain Technologies, Ltd.

Founded in 2013, Bitmain Technologies, described as the world’s most valuable bitcoin company, was established to develop and sell the world’s leading bitcoin miners using Bitmain’s ASIC chip technology. Bitmain is now among the most recognizable companies in the cryptocurrency space and the proud parent of several brands, among them Antminer, Antpool, BTC.COM and Hashnest, all of which are among the leading companies in their respective fields. Bitmain’s machines and customers are present in more than 100 countries across the globe.

Bitmain remains devoted to the production of high quality and efficient computing chips, high density server equipment, and large scale parallel computing software. The company is proudly headquartered in Beijing, with offices in Amsterdam, Hong Kong, Tel Aviv, Qingdao, Chengdu and Shenzhen.

Media Contacts

BitPay — James Walpole | 404 793 6231 | media@bitpay.com

Bitmain — Nishant Sharma | +86 400 890 8855 | info@bitmaintech.com


BitPay Enters Agreement with Bitmain to Develop Open Source Blockchain Security Software was originally published in BitPay On Bitcoin on Medium, where people are continuing the conversation by highlighting and responding to this story.

Bitmain Debunks Antbleed Bitcoin Miners Claim, Apologizes For Bug

An apology has been tendered by the world’s top Bitcoin mining hardware manufacturer as it refutes claims it can remotely shut down its Antminer series of miners owing to a new feature in their firmware. China-based Bitmain on Thursday April 27 released a statement to say that the Antbleed feature was never intended to be malicious as claimed but to empower customers to control their miners particularly at times when the machines are hosted outside their premises.

The Jihan Wu-led company was accused of having the capability to use the Antbleed backdoor to “shut off a large section of the global hashrate (estimated to be at up to 70% of all mining equipment)” and “to directly target specific machines or customers.” If true, this implies that Bitmain could be able to track and control every Bitcoin miners they have sold out to the point of shutting them down remotely.

bitmain

However, in the statement issued by the mining equipment company, it suggests that the purpose of the feature has been misunderstood. Its latest blogpost says:

“This feature was intended to allow the owners of Antminer to remotely shut down their miners that may have been stolen or hijacked by their hosting service provider, and to also provide law enforcement agencies with more tracking information in such cases. We never intended to use this feature on any Antminer without authorization from its owner. This is similar to the remote erase or shutdown feature provided by most famous smartphone manufacturers.”

But the feature was never completed due to some technical problems, the company added. This incomplete state makes it become a bug. As a result, Bitmain apologizes for the bug now being pointed out in the context of the ongoing Bitcoin’s scaling roadmap debate and for the considerable misunderstandings it has caused within the Bitcoin community.

Truly, many in the community have clamoured for Bitmain to come up with an explanation on the issue. Some commentators hold varying views on the issue too.

An industry insider, Tuur Demeester, notes that the Antbleed disclosure would make Wu lose a huge amount of leverage and would “indeed crush probability of BU fork”. For the CEO of Shapeshift, Erik Voorhees, he says in a tweet that he’ll give Bitmain the “benefit of the doubt that AntBleed was a non-malicious feature. Regardless: HUGE security problem, shouldn’t have been done.”

One of the reasons that the issue may not go away quickly is that it follows a series of accusations that have recently been levied against Wu and Bitmain. Wu and his company have been accused of running covert ASICBoost, blocking moves to activate SegWit which has been very controversial in the Bitcoin community and the perception of centralizing the mining chip distribution.

On the ASICBoost, Bitmain was accused of hiding the fact that it has been secretly mining Bitcoin in its own farms with the incompatible and patented hardware which gives miners a 20% advantage over others by exploiting a patchable vulnerability in the network’s protocol. The company denies the claim, cites a smear campaign.

Feature, Bug or Backdoor? AntBleed Code Enables BitMain to Remotely Shut Down AntMiner

The scandals engulfing Chinese ASIC producer BitMain seem never to end. On April 26, a string of code in the AntMiner firmware was disclosed which can remotely shut down some of the mining machines. BTCManager talked with BitMain’s CEO Jihan Wu and a Canadian Miner; a Bug or Feature?

On April 26, the website AntBleed.com went online. It discloses a backdoor in new models of AntMiner, the most popular and efficient Bitcoin mining machine today, which is produced by BitMain, a Chinese ASIC company which has found itself in a growing storm of anger after it started to support controversial Bitcoin client Bitcoin Unlimited.

As the website explains, the software of AntMiner - which is open source, but pre-installed on the shipped ASICs - “checks-in with a central service randomly every one to 11 minutes. Each check-in transmits the Antminer serial number, MAC address, and IP address.” This secret connection to another server is bad, but by far not the worst part of the story; if the remote service returns “false,” the machine stops mining.

With this code, BitMain can shut down every AntMiner of the S9 series, which is every machine shipped after July 2016. It can also, the website continues, target specific miners by serial number or IP address, and shut them down. On top of this, the call to the remote server is not written very securely, so it could be subject to DoS attacks, advanced hacks or the action of large scale Anti-DoS-providers like CloudFlare, which can shut down miners. All this seems to be accurate beyond doubt.

Just a Protection against Miner Theft?

BTCManager reached out to Jihan Wu, CEO of BitMain. He explained:

“It is a feature that is under development and incomplete. It should help mining rig owners to track their rigs that are hosted by third parties. If it is stolen or hijacked, the owners will be able to use this feature to shut down the miner.”

In a statement on its website, BitMain explains the motivation of this development, “This was after more than one incident of miners being stolen from a mining farm or being hijacked by the operator of the mining farm.” The website lists incidents from 2014, 2015 and 2017 when several thousands of units of Antminers have been withheld by hosting service providers.

Due to technical problems the feature, however, has not been completed, Jihan Wu continues. The fact that a malicious party can patch the code very easily makes it in its current state worthless. He admits: “It is a bug to leave the code there, and the testing server has been shut down. We have removed it and released a new version of firmware.”

Not a Killswitch, but a Phone Home Feature?

Before we talked with Jihan Wu, we had a conversation with a Canadian Miner who mines several cryptocurrencies, including bitcoin and maintains a mixed set of different mining machines, including Antminer S9. His explanations are to some parts invalidated by BitMain’s statement, but they nevertheless shed some light of the nature of the code, and he provides an alternative explanation in case you mistrust BitMain’s explanation.

The miner spent the whole night probing the incident. He explained that the remote server the AntMiner software connects to has the DNS address auth.minerlink.com. Currently, this address is not activated, if you ping it, you get no response, but it is possible to locally redirect the DNS address to another IP address by editing files on your system. The AntBleed website provides a server miners can connect to, which runs a script that shuts down the miner if it is affected by AntBleed.

The Canadian Miner we talked with did not want to give an anonymous server his data, so he “put the AntBleed python script on one of a VM and tested it on the whole farm.” The result was that 12 percent of his miners stopped mining, which is most, but not all miners produced after the AntBleed Code was committed to the firmware. He could not provide a reason why some machines kept mining.

Asked if he thinks AntBleed is a remote kill switch for AntMiners, he answered: “I don't think so, it is really the miners that phone home and get a reply from the server. And the phoning home address (auth.minerlink.com) is hardcoded in the source.” To hack this function, you need to manipulate the resolution of the DNS into an IP address on a large scale, which is not a trivial task but could be accomplished by governments or huge DNS providers or Anti-DoS-services like CloudFlare.

At the same time the miner, however, agreed that “Bitmain could shut down all machines that have the phone home feature. And yes, they could target specific customers if they record the IDs before delivering the miners.” On the other hand, the miner explained, “it is trivial to bypass; you just need to add one line to /etc/hosts”. The website AntBleed explains how you can deactivate the phone home function, which might be the patch Jihan Wu said makes the feature currently worthless.

Remote Control and Copyright

The Canadian miner agrees with BitMain that AntBleed is not implemented as a bug or a backdoor, but rather as a feature. He speculated about its purpose:

“A while ago I remember seeing Minerlink. This was BitMain’s idea of remotely controlling and monitoring your AntMiner machine through a website.”

The code disclosed by AntBleed “would phone home with machine specs (IP, MAC address, hashboard ID, etc).”

Since BitMain discontinued its Minerlink project, the website does not currently react to pings, which strongly indicates that the feature has not been used yet. Asked if the code is part of Minerlink, Jihan Wu however denied and explained that it is the opposite: “If the feature is completed, users will be able to set up and configure their own auth server and it does not have to go through Minerlink.”

“It is either a feature to allow you to shut down your miner through minerlink.com,” the Canadian miner continues, “but it can also be a way BitMain found to prevent people from copying his miners.” Similar as it is said that Google has a copyright protection for hardware which allows it to shut down Android machine with fake IDs, BitMain could use the phone home feature to detect and shut down faked hash boards.

Weaponize Code

The code is not malicious, the miner agreed with Jihan Wu:

“I don’t think there is a desire to weaponize it at all. Google can shut down all Android phones instantly. Do they do it? If it were really meant to be nefarious, they would have at least tried to obfuscate the code.”

For the miner, it is clear that this feature was instead “weaponized” by Core fans, which for the past few months have been on a crusade against BitMain because the mining company does not mine for SegWit, but chooses to use Bitcoin Unlimited. The design of the website, the timing of the disclosure and the massive activity on social media at this time indicate that the Miner may be right on this.

But this does not change the facts. The option to remotely shut down a miner, be it by BitMain or by large-scale hackers or governments, is not something that is desirable in the world of Bitcoin mining. Hopefully, the disclosure helps to deactivate it on a large scale. BitMain’s promise to remove it is a step in the right direction.

While on April 26 many people learned that mining is not as secure as they thought, you can conclude, mining has at the same time become more secure as a result of the AntBleed development.

Antbleed: Bitcoin’s Newest New Controversy Explained

A mining chip vulnerability that could potentially be used to remotely shut off bitcoin mining machines was revealed yesterday – with a fix from the manufacturer following shortly after. Involving controversial mining chip manufacturer Bitmain, the issue is what some are calling a "backdoor" in the code that controls its hardware, offering the company a […]

Source

Litecoin: Bitmain Trades Sides, Supports SegWit Activation

Litecoin’s problematic course towards Segregated Witness (SegWit) activation has ended in an unusual display of unity.


Litecoin Roundtable: We ‘Unanimously Agree’ On SegWit Activation

Following a meeting of Chinese cryptocurrency players including exchanges and miners, a consensus was reached on activating SegWit despite some participants having previously been against the idea.

The so-called Litecoin Global Roundtable included Litecoin creator Charlie Lee, exchanges Huobi and Okcoin and formerly anti-SegWit mining pool Bitmain.

Summarized minutes released from the meeting confirm that subject to community support, participants “unanimously agree” to “implement Segregated Witness softfork on Litecoin.”

“When the usage of Litecoin block capacity is over 50%, we will start to prepare for a solution to increase the 1MB block size limit through a hardfork or softfork,” a proviso adds.

Bitmain Gets Behind Litecoin SegWit

The big surprise from Friday’s events was the support of Bitmain, whose CEO Jihan Wu had previously stated his opposition to SegWit on numerous occasions, both for Bitcoin and Litecoin.

Now, it appears, both Wu and Bitmain have U-turned on the idea.

The Roundtable added:

We want to emphasize that this roundtable meeting represents only the consensus of participating members, and cannot make a decision on behalf of the Litecoin community.

U-Turns Abound

Litecoin’s approaching SegWit activation threshold had caused a significant uptick in its price. Having traded at just under $4 per coin for a considerable period, increasing miner support saw it shoot past $10 and stay at these levels.

As interest increased, however, rumors began spreading of manipulation by Bitmain, which was accused by pro-SegWit Shaolinfry of artificially hindering Litecoin’s activation.

Lee himself appealed to the community to force a user-activated soft fork (UASF) to counter such activities. In a further sign of how the situation has changed, the Roundtable members added that they were now against as UASF with a specific activation schedule, stating:

We do not advocate a flag-day ‘UASF’ that does not go through [sic] any users or community voting process. This type of forced upgrade without community consensus put Litecoin in a risk of split

What do you think about the latest events for Litecoin? Let us know in the comments below!


Images courtesy of AdobeStock

The post Litecoin: Bitmain Trades Sides, Supports SegWit Activation appeared first on Bitcoinist.com.

Litecoin: Bitmain Trades Sides, Supports SegWit Activation

Litecoin’s problematic course towards Segregated Witness (SegWit) activation has ended in an unusual display of unity.


Litecoin Roundtable: We ‘Unanimously Agree’ On SegWit Activation

Following a meeting of Chinese cryptocurrency players including exchanges and miners, a consensus was reached on activating SegWit despite some participants having previously been against the idea.

The so-called Litecoin Global Roundtable included Litecoin creator Charlie Lee, exchanges Huobi and Okcoin and formerly anti-SegWit mining pool Bitmain.

Summarized minutes released from the meeting confirm that subject to community support, participants “unanimously agree” to “implement Segregated Witness softfork on Litecoin.”

“When the usage of Litecoin block capacity is over 50%, we will start to prepare for a solution to increase the 1MB block size limit through a hardfork or softfork,” a proviso adds.

Bitmain Gets Behind Litecoin SegWit

The big surprise from Friday’s events was the support of Bitmain, whose CEO Jihan Wu had previously stated his opposition to SegWit on numerous occasions, both for Bitcoin and Litecoin.

Now, it appears, both Wu and Bitmain have U-turned on the idea.

The Roundtable added:

We want to emphasize that this roundtable meeting represents only the consensus of participating members, and cannot make a decision on behalf of the Litecoin community.

U-Turns Abound

Litecoin’s approaching SegWit activation threshold had caused a significant uptick in its price. Having traded at just under $4 per coin for a considerable period, increasing miner support saw it shoot past $10 and stay at these levels.

As interest increased, however, rumors began spreading of manipulation by Bitmain, which was accused by pro-SegWit Shaolinfry of artificially hindering Litecoin’s activation.

Lee himself appealed to the community to force a user-activated soft fork (UASF) to counter such activities. In a further sign of how the situation has changed, the Roundtable members added that they were now against as UASF with a specific activation schedule, stating:

We do not advocate a flag-day ‘UASF’ that does not go through [sic] any users or community voting process. This type of forced upgrade without community consensus put Litecoin in a risk of split

What do you think about the latest events for Litecoin? Let us know in the comments below!


Images courtesy of AdobeStock

The post Litecoin: Bitmain Trades Sides, Supports SegWit Activation appeared first on Bitcoinist.com.

Bitmain Debuts New Litecoin Mining Hardware, Citing Customer Demand

Mining manufacturer Bitmain has announced new litecoin hardware it is aiming to ship in July. The China-based company listed the Antminer L3+ miner on its website yesterday, claiming that it will be the most powerful and efficient of its kind on the market. Published specifications indicate that the miner operates at a peak hash rate of 504 […]

Source

Examining Bitmain’s Claims about ASICBoost

Bitmain recently published a blog post that made several claims about their use of ASICBoost. In this article, I seek to examine their claims.

The Difference Between Overt and Covert ASICBoost

I’ve written about ASICBoost before, but I’ve seen a lot of confusion about the difference between overt (or version-based) ASICBoost and covert (Merkle Root based) ASICBoost. In order to examine Bitmain’s claims properly, we need to understand the difference between the two.

A Little Bit about Bitcoin Block Headers

The Bitcoin block header is exactly 80 bytes long. It consists of the following fields:

Hat Tip to Jeremy Rubin

You can see that version goes from bytes 0–4, previous block from bytes 4 to 36, Merkle Root from 36 to 68, etc.

The key to making ASICBoost work is that the last 16 bytes of the block header has to stay the same through multiple runs of finding proof-of-work. That is, the last 4 bytes of Merkle Root, Time, Nbits and Nonce have to be exactly the same. If so, part of SHA256 can be pre-computed and save a lot of energy in finding proof-of-work.

How Does Overt ASICBoost Work?

Overt ASICBoost keeps the same Previous Block and Merkle Root for every run and changes the version. There are 4 bytes in version, or 32 bits that can be manipulated. This turns out to be plenty for ASICBoost to work and in fact, you really don’t need more than 4 bits or so of the 32 bits.

The problem with overt ASICBoost is that the version field is currently used by BIP9 to signal for various features. It would be obvious to the network if a miner were using overt ASICBoost since somewhere between 1 to 4 bits would essentially be random in every block the miner found.

How Does Covert ASICBoost Work?

Covert ASICBoost keeps the same version and Previous Block for every run and changes the Merkle Root. But note that Merkle Root bleeds into the 16 bytes that ASICBoost cares about. Specifically, the last 4 bytes.

In order to change the Merkle Root, and yet not change the last 16 bytes of the header, a miner would need to find some collisions of the Merkle Root. This can be done by just computing a large number of Merkle Roots. If you find two Merkle Roots with the same last 4 bytes, you can use them for covert ASICBoost.

This is a lot like the birthday problem where you can try to figure out how many people have to be in a room before you find two with the same birthday (the answer, unintuitively, is 23 for about a 50% chance). As Gregory Maxwell pointed out, you actually only need to calculate about 2¹⁶ different Merkle Roots before you have a 50% chance of finding a collision in the last 4 bytes. To find 4 Merkle Roots that have the same last 4-bytes (like the number of people in a room before you have 4 with the same birthday), is 2²⁴ different Merkle Roots.

To calculate that many Merkle Roots efficiently, you need to calculate a lot of left halves and a lot of right halves. To get 2²⁴ Merkle Roots, you would need 2¹² left halves and 2¹² right halves. You can combine every left half you have with every right half you have to get the 2²⁴ Merkle Roots. Calculating different left halves is pretty easy. You can change the coinbase transaction slightly and recalculate the left half (note the coinbase transaction always lives on the left side, as it’s the first transaction).

Calculating the right half is a little more complicated. This is because you don’t want to change anything on the left half, specifically the coinbase transaction (incidentally, this is why Segwit is involved in all this as changing anything, including order, on the right side changes the coinbase transaction when segwit is activated). Remember that the coinbase transaction distributes to the miner all the mining fees from every transaction. So if you change the mining fee on any transaction on the right as a part of calculating a new right half, your left sides all are no longer valid. Thus, what you have to do is make sure the fees stay the same, but change the right side hash. This can be done several ways, including substituting with a transaction with the same fee, changing the order of transactions, etc.

To get 2¹⁶ different right sides, you need 9 transactions to change the order on. If these 9 transactions have the same exact fee, even if the block was strictly ordered by fee, this makes covert ASICBoost completely undetectable as those 9 transactions can be switched around with impunity.

I’ve examined about a day’s worth of blocks on mainnet and have concluded that most blocks have way more than 9 transactions that are both on the right side of the Merkle Tree and have the exact same fees. Essentially, every block (mined by different pools) could have used covert ASICBoost or not used covert ASICBoost. There’s no way to know by examining the blocks or transactions or fees.

Another thing about the covert method. You can generate 2²⁴ different Merkle Roots by creating an empty block and that would be a bit simpler, though still require a lot of RAM. More technical details and how efficient this method with respect to the overt method are here.

Some Facts about Covert ASICBoost

Covert ASICBoost requires a lot of memory. You need to store about 2²⁴ Merkle Roots which are 32 bytes at a minimum. That’s 256 MB of really fast memory, and probably more to accommodate for unlucky searches. You can reduce this memory requirement by getting less collisions.

You need a lot of transactions in order to use the Merkle Tree method. You need at least 25, preferably more. This may not sound like a lot to those used to Bitcoin, but most other coins, including testnet, have a lot less transactions per block.

Covert ASICBoost is a lot more complicated than overt ASICBoost. You need a lot of memory, you need to calculate a lot more hashes and you need to do a lot of transaction shuffling. Overt is a lot faster and easier to design than the covert method.

Neither overt nor covert ASICBoost are currently supported by the Stratum protocol, which is the default mining pool software protocol. Overt needs to change version bits and covert needs to change the right side of the Merkle Tree, both of which are impossible with Stratum.

Bitmain and ASICBoost

Bitmain claims to have tested ASICBoost on Testnet, but have not used it on Mainnet. This only refers to overt ASICBoost. They specifically referred to covert ASICBoost as “not practical in a production environment”. Further, they claim their circuit design supports ASICBoost, but that almost certainly refers to overt ASICBoost only.

Examining Claims

Testing overt ASICBoost is really easy on Testnet as block headers would have weird version values. Indeed this seems to be the case as I’ve shown in the code published here. There are a bunch of testnet blocks around block 300,000 (October 2014) which have version fields that look pretty random and aren’t used ever again. Normal blocks near those blocks have the version number of 2. The same analysis on mainnet blocks shows that there are no weird version-number blocks.

Testing covert ASICBoost would be a little bit challenging. Most blocks on Testnet don’t have enough transactions to be able to test covert ASICBoost properly. Remember, you need about 9 transactions on the right side of the Merkle Tree. You can, of course generate your own testnet transactions. You can also test the empty-block method.

Note this breakdown of AntPool’s (owned by Bitmain) stratum extensions seem to support Bitmain’s claims of having used overt ASICBoost but not covert ASICBoost. Multi-version refers to overt ASICBoost, or how many bits can be used in the version field of the block header. Covert ASICBoost as explained by Greg Maxwell would require additional data, like what transaction ordering is required on the right side of the Merkle Tree, or which transaction hashes need to be in what position, which isn’t in that hidden configuration or their source code for implementing Stratum.

Conclusion

In this light, Bitmain’s claims of having used overt ASICBoost on Testnet, but not on Mainnet are fully consistent with the data on their respective blockchains. Specifically, it looks as though overt ASICBoost was tested by someone (likely Bitmain) around October of 2014.

Bitmain claims not to have implemented covert ASICBoost (they claim it’s impractical), and that’s also consistent with the data on both blockchains. It must be explained here that covert ASICBoost is relatively easy to hide on Mainnet given the number of transactions with the same fees and no general required ordering of transactions exist in Bitcoin other than being topological sorting (that is, dependency order). Covert ASICBoost could also have been used on Testnet, but with more difficulty.

The evidence on both blockchains are fully consistent with Bitmain’s stance (only used overt ASICBoost and only on Testnet) and Greg Maxwell’s stance (covert ASICBoost may have been used).

It is my opinion that to determine whether covert ASICBoost has been used, a line of inquiry into whether 256 MB (or thereabouts) of fast memory is practical given the price of Antminer’s equipment and whether there is evidence of Stratum extensions that specifically order the right side of the Merkle tree would be the most fruitful in terms of settling claims of covert ASICBoost usage.