Emergency Update 0.17.2

Originally published here.DOWNLOADS HERECRITICAL MESSAGE FROM BTG TEAM TO ALL POOLS, EXCHANGES, WALLETS, SERVICES, AND COMMUNITY RUNNING NODESPlease immediately upgrade your BTG Core full nodes to version 0.17.2, published July 2, 2020.HOW TO UPGRADE:You can use the pre-compiled binaries on Github , or use the DOWNLOADS link you see above. Simply stop your node, install the upgrade, and start your node again.Or manually upgrade from the latest code on the BTCGPU Github v0.17.2 tag (on 0.17 / master branch); full release notes here. If you are still at v0.15.2 and haven’t upgraded to 0.17, we have a backport version v0.15.3 tag (on 0.15 branch) including the same changes so you can keep your current configuration files.(Note: there were potentially breaking changes in the configuration file between v0.15 and v0.17, see notes at bottom.)If you cannot yet update, you can run this command in the debug console or via bgold-cli to ensure you are on the honest chain:invalidateblock 00000000635620f22ba8694aea532d51619f8cd060f4e42e85db3cb3a5d1c29cNote: a strong majority of the honest mining pools have already upgraded their code a week ago, and they continue to mine on the honest chain.The BTG Explorer at https://explorer.bitcoingold.org/ is on the honest chain. You can compare your most recent blockhash with the explorer to ensure you are on the honest chain.To ask your node for the latest blockhash, give it the command:getbestblockhashAnd compare it to the latest block on the BTG Explorer at https://explorer.bitcoingold.org/ by clicking into a block and looking at the BlockHash at the top. Example:EMERGENCY INFORMATIONWe have just seen an extremely long attack chain of over 1300 blocks on July 10, 2020, against the BTG network which have been mined since July 1, 2020.We detected this illicit activity early on and sent alerts to pools and exchanges to protect them; many closed their wallets over a week ago. We also supplied them with BTG version 0.17.2, which included a checkpoint at:block 640650, hash 000000059ec8884fa4fbbdbe46c09cfb4ecba281dfa2351a05084e817c1200aeWhich was mined July 2 at 2am UTC, by MiningPoolHub, a known honest block.With this block checkpointed, the attacker’s chain could not take over, but this information was not public, and the attacker continued to mine. The attacker mined their secret chain for nearly 10 days, renting power from NiceHash to do so. Today, on July 10, the attacker released over 1300 blocks.Because those attacking blocks are anchored at a block mined on July 1st (before the checkpoint), the honest pools and exchanges who are running the updated code automatically rejected the attacker’s chain.It’s time for everyone else to upgrade their nodes. If you cannot upgrade, you can push your node onto the honest chain by using the simple command:invalidateblock 00000000635620f22ba8694aea532d51619f8cd060f4e42e85db3cb3a5d1c29cIf you use the Bitcoin Gold GUI, you can enter this command in the Debug Console. If you use the command line daemon, simply give this command to bgold-cli:bgold-cli invalidateblock 00000000635620f22ba8694aea532d51619f8cd060f4e42e85db3cb3a5d1c29cThis tells your node that the attacker’s version of the block at height 640650 invalid, and your node will immediately switch back to the honest version of the chain (perhaps after a short recalculation delay.)The majority of honest pool hashpower continues to mine on the honest chain.Questions can be addressed to the BTG team:On DiscordOr on TelegramAttack chain detailsThe attacking chain includes this block at height 640650:00000000635620f22ba8694aea532d51619f8cd060f4e42e85db3cb3a5d1c29cThe honest block checkpointed in version 0.17.2 at height 640650:000000059ec8884fa4fbbdbe46c09cfb4ecba281dfa2351a05084e817c1200aeThe attacker’s mining coinbase address was:GcxCUDhfB7RwfScd96J24mKYPounRbVUq2Their common ancestor, valid on both chains, is block 640568, hash 00000001ca8ac90d83f6f5da01ac96b7a017702a040953b93cda2e52b07385cd,The honest chained mined publicly, mining this block 640569 on July 1st:000000027cd13938b688121c272c523497f898bcc743f2793b3eaeaa7abd751aThe attacker mined secretly and withheld their block 640569 until July 10th, even though it was mined July 1st:000000047bd388dd484d9fdadece6b71aa13fa987bd2a283b68b9a2968465eacIf you have previously updated to BTG Core 0.17.2, you will still be on the honest chain, along with the major mining pools and exchanges.If you have not yet updated and cannot update at this time, run the invalidateblock command as noted above to discard the attacker’s chain and put your node on the honest chain.*Regarding potentially breaking changes in the bitcoingold.conf file: these changes are aligned with the changes in Bitcoin Core v0.16 and v0.17 and include deprecated RPC commands which are now disabled by default, as well as the introduction of “sections” for testnet and regtest. If you must use deprecated RPCs that are now disabled, you can re-enable them in your config file with the appropriate deprecatedrpc flags. Commands that are not in a section for [test] or [regtest] will only apply to mainnet; see ReleaseNotes. If you use no deprecated commands and use your config file only for mainnet, there should be no breaking changes.

Presenting CCBN

A decentralized way to prevent double-spends from 51% attacks.Originally posted here alongside draft whitepaper with full details.A brief overview of CCBN:What is Notarization, and how does it work?BTG blocks are Notarized to well-known public blockchains which serve as our “Notarychains.”Notarizations contain complete BTG block headers with the solution hashes (so they cannot be easily faked.)Notarizations gain Weight based on their depth in the Notarychain. Those made earlier gain Weight faster than those made later.When are Notarizations used?When a competing chain of blocks (a fork) appears, BTG nodes with CCBN do not switch to the longer chain immediately.Instead, they check the Notarychains to calculate Weight and will only switch to a longer chain that also has more Weight.If a “natural” fork occurs and all blocks are Notarized, CCBN has no effect. No change to normal PoW (Nakamoto Consensus.)Secret Mining Attackers are faced with a dilemma:If a Secret Miner Notarizes blocks, they become public!Key parties (like Exchanges) can see the Notarizations and will not confirm deposits.But if a Secret Miner does not Notarize …When they later publish their Secret chain, nodes refuse it because of low Weight, preventing the attack.Either the first spend is refused by the Exchange, or the second spend is refused by the chain.Either way, a Double-Spend fails!It’s a soft fork!CCBN is essentially a backup Consensus method, used only to arbitrate a chain split in favor of the honest chain.Simulations show that notarizing to well-selected Notarychains provides > 99% protection against attacksFully Decentralized: No masternodes, notarynodes, federations, consortia, or privileged parties.

BTG Core Wallet v0.17.1 RC1

We’re thrilled to announce the Release Candidate of BTG Core wallet v0.17.1This major update to our Full Node wallet includes substantial new features for BTG and numerous bug fixes.You can download the new Release Candidate here.This release will likely become the final release; it has been extensively tested, but remember this is still a Release Candidate and there may still be bugs to be discovered. Typical users can shut down their node, install the new version, and start their upgraded node without issue, but it’s always best to backup everything, especially wallet.dat files, first.As promised, BTG strives to stay in-sync with Bitcoin Core’s developing features. BTG Core v0.17.1 parallels features of Bitcoin Core v0.17.1; developers and engineers can expect to see the same changes they already experienced upgrading Bitcoin Core from version 15 to versions 16/17.IMPORTANT: Do not use v0.17.1rc1 for in-place node upgrades in production environments without first testing and modifying! This version makes important changes to some APIs and the conf file (see release notes). Also, if you run a full transaction index (most individuals don’t choose to do this), the txindex db will be migrated, which can take many hours before the node is usable again.Notable ChangesCompact BlocksThe most immediately important feature: Compact Blocks are fully implemented on BTG for the first time. This enhancement is critical to support Light Wallet protocols like Neutrino, which enable Lightning wallet and mobile wallet apps to work directly with the BTG network without having to download and store the whole blockchain.Wallet EnhancementsThe wallet and user interfaces now fully support Segwit addresses and full native Segwit support is enabled. All new wallets are HD-wallets (hierarchical deterministic — until now, users still had the option of making a new wallet that was not HD.)PSBT SupportBitcoin’s PSBT interchange format is introduced for BTG in this version, though it is not yet supported in the GUI. PSBT allows for transaction creation and signing to be coordinated among multiple parties (for hardware wallets, multisig systems, CoinJoin, etc.)For Developers and EngineersWith this version, the RPC changes and new ‘label’ API you may know from Bitcoin Core versions 16 and 17 are now in place for your BTG nodes. Developers need to be aware that the deprecated ‘getinfo’ API is now retired in favor of more specific calls (see this about the API change) and pool operators need to be aware of the impact to stratum implementation (see this GitHub example for a guide. )Summing UpWhile this new version is not a hard fork and is not a required update (your current nodes will continue to work just fine), it will be a recommended upgrade for all users because of the many improvements. This updated version of the BTG Core Wallet delivers bug fixes, enhances performance, and delivers critical features that enable many new technologies that have been held back until now.Looking forward as always, The Bitcoin Gold OrganizationDevelopers and interested parties can see the work on projects like neutrino, lnd, and other projects on the BTG project’s GitHub.Join the discussion and comment on this post at forum.bitcoingold.org

Leadership for Another Year

It has been just over a year since the Bitcoin Gold project launched. Since then, we’ve been striving to carefully shepherd our young project towards being a fair, transparent, and above all, decentralized cryptocurrency. We observed our One Year Anniversary on November 12th with a refreshed website. Today we have some news about changes in our leadership.We want to share with the community that Jack Liao, who first inspired the Bitcoin Gold Project, is stepping down from the Board. His future involvement will be limited to an Advisory capacity. Jack Liao is a colorful individual and a force of personality who brought vision, energy, and an extensive network in the crypto community to the project. He was the first founder of the Bitcoin Gold project and helped build the team of six co-founders.Jack inspired us and encouraged us to do something ambitious. For that, we will be eternally grateful.At this time, Jack wants to focus his time in other endeavors, encouraging competition and diversity in the crypto space, and his continuing as CEO of his company, LightningASIC. We wish him good luck in all his future endeavors.We also want to share that fellow member of the Board and Lead Developer, H4x3rotab, has decided to publicly share his identity. While we will all still know him as H4, he is no longer anonymous. Hang Yin studied Computer Science at Fudan University and was, until recently, a Google software engineer. He has given up his role at Google to focus all his time into crypto-related work, especially the BTG project.Our team has grown a great deal since our start in 2017, bringing in fresh energy and ideas. We’re excited to see fresh attention and new interest from the crypto developer community — we’ll always welcome new contributors. We’re looking forward to sharing the next year of journey with our growing Community!Gratefully, most sincerely, and with best wishes,The Board of the Bitcoin Gold Organization#1CPU1VoteOriginally posted here.Join the discussion on our Forum here.

Endowment Wallet Mining Pro...

Aug 10, 2018 | Development, Technical, UpdatesSince the day they were first mined, the Endowment’s wallets have been public on the BTG blockchain, but rumors and misinformation persist. This post explains the Endowment mining process in detail and lists all of the wallets.In 2017, the Bitcoin Gold project duplicated (forked) the Bitcoin blockchain as a fair way to distribute 16 million coins, and then launched with an 8000-block mining period to create a 100,000 BTG Endowment to support the future of the project.As of early August, 2018, about 20,000 BTG have been spent from the Endowment and about 80,000 BTG remain.This Endowment is currently the only source of funding for the Bitcoin Gold project; after the formation of the Endowment on the day of launch, 100% of all mining rewards and fees have gone directly to the miners — exactly as described in our original Bitcoin Gold Whitepaper / Roadmap. and detailed in our earlier Endowment post.The funds we’ve spent from the Endowment align as described in the Roadmap — salaries and payments for infrastructure, developers, support staff, travel to promotional events… we have not spent any funds paying Exchanges to list BTG. Our developers are currently focused on bringing Lightning Network fully to life on BTG, and are working on Atomic Swaps, Smart Contracts, and more!The whole team is working hard to be Good Stewards of the Endowment so that it can support this project for months and years to come, despite the temporary bear market in cryptos.Building for the future, The Bitcoin Gold Organization #1CPU1VOTENote that there is no “new information” in this post– it is a summary of information that has been publicly available since launch in 2017, either in the public open-source code on GitHub, or on the BTG blockchain itself.Recap of how BTG startedFork and Launch:Fork at BTC Block 491406After Bitcoin block 491406 was mined on 2017–10–24 01:17:35 UTC, there were about 16.5 million Bitcoin in existence. At that point, the entire Bitcoin blockchain was duplicated (forked) to establish the starting point of the ledger for BTG — so BTG blocks 0 through 491406 are identical to those same-numbered Bitcoin blocks (with the addresses converted to BTG format to avoid confusion.)This new ledger of BTG had the same number of coins in it — 16.5 million — each of which was in the control of the same owner as the original Bitcoin (because those people hold the private keys).BTG Network LaunchOn November 12th at 08:34:01, the BTG network was launched and mining began with BTG block 491407, the first block mined as BTG, on 2017–11–12 12:34:01 UTC.There was no mining and no coins were created between 2017–10–24 and 2017–11–12.The mining reward from the first 8,000 BTG blocks formed the Endowment. At a block reward of 12.5 BTG per block, 8000 blocks yields 100,000 BTG, as specified in the original Bitcoin Gold Whitepaper / Roadmap.Of those 100,000 BTG, 40,000 were immediately accessible and 60,000 were time-locked for up to 36 months. For safety, security, and control, those 100,000 BTG were mined into 152 different wallets, and all of these wallets are 4/6 multi-sig. (This means there are six private keys for each wallet, and at least four of the six private keys must sign a transaction to move any funds. Each of the six co-founders of the project holds one of these keys.)If you’re good with code, you can confirm what’s written above by looking at the open-source code in our GitHub: 60% of the funds being time-locked for up to three years can be seen here. Enforcement of the official multisig wallet list is in the consensus rules seen here. If you’re not good with code, you can read still understand full mining process below, along with a full list of all the Endowment wallets. We include links to the blockchain explorer to make it easy to confirm on-chain.After the mining of the 100,000 BTG of the Endowment, the total number of BTG rose from 16.5 million to 16.6 million. The Endowment was only 0.6% of the coin supply at the time. (Max future coin supply is 21 million, so the Endowment was 0.476% of the maximum coin supply.)Endowment Mining SpecificsFirst 3200 blocks (40,000 BTG)These were mined into four wallets, “round robin” style:491407 -> Address 1 491408 -> Address 2 491409 -> Address 3 491410 -> Address 4 491411 -> Address 1 491412 -> Address 2 491413 -> Address 3 491414 -> Address 4 491415 -> Address 1…… and so on for 3200 blocks. At 800 blocks per wallet, these wallets accumulated 800 * 12.5 = 10,000 BTG each. The wallet addresses are listed below, and are also visible when looking at those block numbers in any BTG blockchain explorer.The next 4800 blocks (60,000 BTG)The remaining blocks were divided into roughly 36 segments to unlock monthly over the course of three years. (Dividing 4800 into 36 would actually be 133.33 blocks per segment; instead, 36 segments of 133 blocks were created and a 37th segment with the remaining 12 blocks.)Each segment was mined round-robin into four wallet addresses, much like the earlier blocks.Example:494607 -> Address 5 494608 -> Address 6 494609 -> Address 7 494610 -> Address 8 494611 -> Address 5 494612 -> Address 6 494613 -> Address 7 494614 -> Address 8 494615 -> Address 5…During the first 132 blocks of the segment, each address received 33 block rewards of 12.5 BTG, so each received 412.5 BTG. Then, for the 133rd block, the first address received an additional 12.5, bringing the total to 425 BTG in the first wallet.The total BTG for the segment is 425 + 412.5 + 412.5 + 412.5 = 1,662.5 BTG.After these 133 blocks were done, mining advanced to the next segment, which did the same procedure into four new wallet addresses which were time-locked for an additional month.Again, all the addresses in question are 4/6 multi-sig and require four signatures to withdraw funds, in addition to the time locks.Complete List of Endowment WalletsAs of early August, 2018, about 20,000 BTG from the 100,000 BTG Endowment have been spent, and 80,000 BTG remain in the originally mined wallets. Nearly 60% of the current funds remain time-locked.The complete list of Endowment mining blocks and their wallets follows below, broken into segments as described above. The first column shows the first block mined for each wallet; the second shows for how many months that wallet was locked.Links go directly to the noted wallet address or block in the official BTG explorer, but these can be verified in any BTG block explorer or full node.Full list available here.

Bitcoin DLL Vulnerability, ...

Responsible DisclosureAs you may be aware, Bitcoin Gold has a Responsible Disclosure policy listed on the website, which is basically a (bug) bounty program for reporting security vulnerabilities in our stable software versions or infrastructure.It allows people to safely report an issue to us, and if they follow the rules set out in the Responsible Disclosure policy, we will not take any legal action against them in regard to the report (hacking is still illegal).The ReportThrough the end of March, we received only false reports of “non-existing” issues, which we rejected. However, we recently received the first report which our SYSOPS and CERT team could accept. Although the security issue was very minor, we acted on it directly.It was a DLL vulnerability that affects Bitcoin and all coins that use Bitcoin’s installer methods (including BTG.) We used the fix in our recent Network Upgrade and shared it for the rest of the community’s benefit.Timeline:You might have noticed there was a sizable time span between the report and the fix. That is correct: it takes time to build a fix, especially if the issue stems from a third party module and your entire build process is wrapped around it. It took a long time to test, build, and test again before we could implement the fix as a replacement for our current build process.The FixThe specific issue addressed by the bug was as follows: Bitcoin Gold uses the NSIS Installer module, which basically wraps our code into a nice install package for people. Our code uses the v2.46 NSIS installer module, the same as in the Bitcoin source. This outdated code had a bug in LoadLibrary: by default, it looks in the current directory of the process and into the Folder of the Executable. This is bad (especially in common use case when users execute our installer from the downloads folder) because an attacker is able to drop a DLL into the Folder of the Executable and give themselves high privileges. To try it out, just place a fake shfolder.dll (which brings up a message box in its DllMain) in the same directory as an NSIS installer and run the installer to see the message box appear. This bug has recently been found in many products and is called ‘.DLL sideloading’ or ‘.DLL hijacking’. Only Windows 7 and very old builds of Windows 8 are vulnerable. An updated Windows 8.1 or any Windows 10 system is not vulnerable.Although the fix may appear easy (just install the new version 3.03 NSIS installer module!), it is, unfortunately, not that simple. With deterministic builds, we have to make sure the installer matches our code, which involves a lot of trial and error. Also, with our upcoming Upgrade hardfork and another update in the code, all updates needed to be added into the latest releases (as they are mandatory upgrades.)Our developers did the careful work necessary to implement the new module into the existing build process before our next release. Any developer that is interested in how we resolved the issue can find our fix on our GitHub repo code commit, Switch to NSIS 3.03 (borrowed some code from TOR project).The (low) RiskTo be clear, your system had to be compromised in advance for the attacker to have used this vulnerability. The installer software was not compromised, nor was our code modified or hacked. An attacker had to download a malicious .DLL file and put it in the same folder where you downloaded and run the installer. The Bitcoin Gold code, daemon and cli are not affected, nor is any Linux or Windows system (8/10) that is up-to-date. Even if you are running Windows 7, it’s unlikely that an attacker would have been able to download a malicious .DLL file into the right folder at the same moment as you launched the installer. And users would only install a (new) version once on its system.Our recommendation: remove any and all previously downloaded installers and only use the latest version from our website or Git repository.Because this fix was implemented well before our recent Network Upgrade on July 3rd, everyone who downloaded our software or code in preparation for the Upgrade was safe from this vulnerability.It’s important to note that this issue is not specific to Bitcoin Gold: it can affect any coin that uses Bitcoin’s code as a basis. Some repositories, including Bitcoin itself, are currently vulnerable to this issue.To ensure awareness of the issues and the fix, we submitted our work to the Bitcoin code repository in this Pull Request: Switch to NSIS 3.03 to avoid DLL hijacking.CreditsThe BTG team would like to thank the original Reporter (Shah from FortiGuard Labs), the TOR Project (where helpful code was sourced), and we’d like to call out the efforts of our SYSOPS and DEV teams, who managed the issue and the resolution for us. We’re happy to be able to contribute back to the Bitcoin project and provide a fix which can potentially be used by multiple projects which rely on the Bitcoin codebase.Supporting the ecosystem,The Bitcoin Gold Organization#1CPU1VOTEOriginally published here: https://bitcoingold.org/bitcoin-dll-vulnerability-and-fix/

Lightning Network Technical...

We have a treat from our developers — a Technical Preview release of Lightning Network running on Bitcoin Gold!Our devs have successfully brought to life all the core functions for a BTG-based implementation of Lightning Network, based on LND (the Lightning Network Daemon) from Lightning Labs. This release provides a Technical Preview version that other developers can test and experiment with.What is Lightning Network?It’s a brilliant way to create super-fast, micro-cost BTG payments with virtually no limits to the transactions per second or the number of users.Lightning Network payments take place through payment channels directly between users, without waiting for blocks on the blockchain, so they are instantaneous. At the same time, the payments are reliable and trustable because of the way those payment channels are created and funded: with smart contracts on the blockchain.Because Lightning Network depends on a Segwit-enabled blockchain (like the BTG blockchain) as a base layer where the channels can be created, it’s often called a “second layer solution.”The last piece of the puzzle? Routing:RoutingOn the Lightning Network, two people don’t need a direct channel to send money to each other because the payment can travel across many peoples’ channels. As long as there’s a path between people, the network can route the funds between them. The payment “hops” through channels between multiple people to reach the recipient, and clever cryptography within the Lightning Network payment system ensures that nobody in the chain gets paid unless everybody in the chain gets paid. And since each individual transfer is instantaneous, the entire chain of payments can be completed in a moment!This code is backed by solid engineering, but the combined effect is somewhat magical. Channels between nodes are secure and trusted because they’re based on coins and contracts on the base-layer blockchain. Meanwhile, payments across those channels in the second-layer Lightning Network happen instantly, without waiting for the blockchain, by flowing through those pre-established channels.So Lightning Network is super-fast — but how is it micro-cost?The cost of opening or closing a channel is based on the cost of transactions on the blockchain — every new channel puts activity on the underlying blockchain, which incurs a fee. But, once a channel is opened, it can be used for thousands of payments without touching the blockchain again, so none of the payments incur that cost. Each Lightning Network payment includes a tiny, tiny fee which is paid to the node that relays a payment. The tiny fee is so small it’s almost negligible, but it gives people an incentive to allow their nodes to serve as relays, and it also prevent spamming (if transactions were completely free, someone could write bots to just push massive number of tiny payments to try to cause trouble.)What it All MeansWhen many thousands of people have Lightning Network nodes, this system is capable of sending millions to billions of transactions per second!!! Without changing the underlying blockchain, Lightning Network delivers:instant transactions — payments in a fraction of a secondphenomenal scalability — perhaps millions of transactions per second before a block size needs to be increasedtiny fees so that even true micropayments are possibleAnd that’s just the beginning — the advent of Lightning Network provides the basis for future developments. When Lightning Networks for different blockchains are compatible, transactions can be made across blockchains in what’s called a “cross-chain atomic swap.” You’ll be able instantly trade BTG for Bitcoin or Litecoin with someone else, without involving an Exchange, without needing an escrow, and without needing to trust the other party!The Technical PreviewIf you’re adept enough to install a computer language, compile code, and configure software, you can go ahead and install our LND implementation from this GitHub repo, and play with it yourself. There isn’t yet a graphical user interface, and it’s only intended for use on the BTG testnet at this time, but the code is fully functional and you can walk through the Lightning Network Developers tutorial with it. (Our implementation is being built to fully compliant with the BOLT specification.)For those of use who aren’t ready to compile and configure our own nodes manually, there’s a walkthrough below of how the technology works; you can see what we’re already able to do on the BTG Lightning Network.GratitudeWe’re excited about the possibilities this new technology brings (you should be, too!), and that’s why we’re working hard to bring it to fruition on our blockchain — but we’d be remiss if we didn’t mention that the open-source LND code we’re working on is being developed by Lightning Labs, who announced their first mainnet beta of Lightning for Bitcoin just a few months ago, and we want to thank the authors of the original Lightning Network whitepaper, Joseph Poon and Thaddeus Dryja.As always, we’re grateful for the fantastic community of open source developers working on exciting projects today and we look forward to making our own contributions to these projects in the future.Building better every day, The Bitcoin Gold Organization #1CPU#1VOTELightning Network Technical Preview: a Basic WalkthroughDevelopers can install our Technical Preview and perform the walkthrough with real nodes, but for the rest of us, here’s a description of what we’re now able to do on BTG with Lightning Network.Let’s say that Alice and Bob want to be able to interact. First, they each set up a Lightning Node of their own:They’ve set up software on their computers, but they haven’t touched the BTG blockchain, yet.Now, Alice opens a payment channel to Bob, and funds it with 1 BTG:Alice and Bob can both trust this channel because it is opened as a smart contract on the blockchain and they each hold one of the multi-signature keys for the contract. In the channel, Alice has 1.0 BTG, and Bob has none.Next, Alice sends 0.2 BTG to Bob:This transfer was instantaneous! It didn’t have to wait for a block, because the channel still contains 1.0 BTG, same as before — but now Alice has 0.8 and Bob has 0.2. If they were to close the channel now, the smart contract on the blockchain would give Alice 0.8 and Bob would get 0.2 — but let’s say they don’t close the channel. They leave things up and running.Now, let’s add Charlie to the picture. He puts up a node:And then Charlie opens a channel with Bob, funding it with 0.2 BTG:Again, creating the channel happens as a smart contract on the blockchain where Bob and Charlie have keys, which contains 0.2 BTG. Only Bob and Charlie trust this new channel.Now, the magical part — it’s easy to see that Charlie can send money to Bob, but Charlie can also send money to Alice, even though they don’t have a channel! Here’s Charlie sending 0.1 BTG to Alice through Bob:Charlie sent 0.1 to Bob, and Bob sent 0.1 to Alice, and it was all instantaneous, because this “multi-hop” payment happened without involving the blockchain. And Bob didn’t even need to be around to handle the two transactions; his Lightning Node was there to serve a purpose, connecting other people. In a large network these payments can go through many people to reach their destinations. It’s like a chain reaction, money flowing quickly through the network like lightning!Notice that the Alice-Bob channel still contains 1.0 BTG, and the Bob-Charlie channel still contains 0.2 BTG. This is how many BTG are locked on the blockchain smart contract for their channel.Here’s one last image, the same as the previous one, but you can see how the two channels are tied to the blockchain:This is why the Lightning Network is a second-layer solution. The coins actually stay in the base layer of the blockchain, but are locked up in a contract between the two people who open the channel. Lightning Network creates the channels where those coins can move back and forth without needing to update the blockchain — and lets networks of people move coins across multiple channels — instantly.Alice, Bob, and Charlie can move money back and forth thousands of times, without making transactions that take up space on the blockchain! And because they don’t touch the blockchain, the fees are super-low — so low that they can be sending 0.00000001 BTG back and forth thousands of times.Instant, Super-Scalable, Tiniest Fees: Lightning NetworkOriginally published at bitcoingold.org on July 12, 2018.

A Successful Network Upgrade

Block 536200 was mined Jul 3, 2018 at 9:59:26 PM UTCUnlocked: New PoW, Equihash-BTGUnlocked: New DAA, LWMAThe Network Upgrade was a success, the blockchain is stable, and all partners can resume regular activities — including returning confirmation requirements to pre-fork levels.Now delivering: greater safety, greater stability, and renewed ASIC resistanceIt has been a long, hard couple of weeks, but we made it!For anyone who doesn’t yet know:Equihash-BTG, our new Proof of Work algorithm, can’t be mined by current ASIC miners, but can be mined by GPUs. So, this kicks them out of our pools.The new algorithm also comes with personalization that makes it harder to re-direct mining power through a “hashrate market.” The recent “51%” attacks, which may or may not have involved ASIC miners, were channeled through hashpower rental markets — but with this change in PoW, there’s no longer a rental market for the algorithm we’re using, and it’s harder to set one up than before. This means more safety.Meanwhile, LWMA, our improved Difficulty Adjustment Algorithm, makes our blockchain more responsive to shifts in hashpower so that the block time is more stable. The GPU hashpower market has become more liquid than it used to be, with more miners adopting “auto-switching” in pursuit of profit instead of supporting specific coin projects. As a result, hashpower can move quickly after a price move in one of several coins, leading to unstable block times. With our improved algorithm, the blockchain adjusts more quickly, providing a steadier flow of blocks.Both improvements are up and running as expected.A few technical notes about the new PoW algorithm, Equihash-BTG, are in order. It consumes vastly more memory than traditional Equihash, so ASICs are no longer able to mine, but GPUs with 3GB VRAM or more can keep working. It’s also important to understand that the new algorithm is about 15 times harder, so each miner produces about 1/15th as much hashrate as they did before. This means that our pre-fork network hashrate of 25 to 30 MSol should be expected to decrease to between 1.6 and 2.0 MSol — which is precisely the range where we stabilized after the hardfork! We’re delighted to see we’ve had no net loss of miners due to the PoW change!The new Difficulty Adjustment Algorithm also appears to be performing just as well as we hoped. At the time of the Upgrade, the Difficulty was intentionally dropped* down sharply, so the initial 45 blocks after the hardfork came rapidly — just under 2.5 minutes per block. Then the new DAA kicked in (when the required 45-block averaging window filled up) and began adjusting the Difficulty upwards based on the block time, bringing the average block time up to the 10-minute target within a day.Safety and stability. Two great improvements that everyone can appreciate!In the three days since then, the block rate has been much more consistent than it was before, both because of our escape from the volatile hashpower rental market, and because of a better-balanced and more responsive DAA. On top of that, the removal of the rental market means the removal of a major attack vector, resulting in massive improvements in safety and stability. That’s two great improvements that everyone can appreciate!A Bit of ThanksWe’re grateful to our diverse pool of miners — and our network of mining pools — for working hard to get through this critical period. Now that the blockchain is stable, it’s safe for all our partners, including exchanges, to resume regular activity. Everything is back to normal, so it’s time to get back to work — including reopening wallet systems and returning confirmation requirements to pre-fork levels.Everything is back to normal, so it’s time to get back to work.We appreciate the hard work and confidence shown by all our partners — miners, pools, exchanges, wallets, explorers, merchant services — this upgrade kept everyone busy before and after the fork, and we thank them all for their diligence. Any partner experiencing any difficulties is more than welcome to reach out to the team for assistance.Up Next — Great Things!We know that this a milestone, not an endpoint. It’s just a waypoint we pass on the way to better things. And though a lot of us have been focused on this hardfork, others have continued working other projects — so we have many great things to share with the Community in the coming days and weeks!Looking forward with excitement,The Bitcoin Gold Organization#1CPU1VOTE*The Difficulty was dropped to compensate both for the harder Equihash-BTG mining, and to compensate for an inevitable temporary reduction in miners at the time of the transition due to miners needing to shut down, make changes, and start up again.Originally posted on the Bitcoin Gold website; discuss this article here or on our Forum.

ElectrumG — Release 3.2.1

The BTG blockchain has been performing wonderfully since the successful Network Upgrade last week. If you’re using our ElectrumG wallet, make sure you update to the latest version, published last week:ElectrumG 3.2.1ElectrumG 3.2.1 is a stable release and is fully compatible with the recently Upgraded Bitcoin Gold Network.What is ElectrumG?ElectrumG is our version of the popular Electrum Bitcoin Wallet, modified for BTG. It’s is a full-featured wallet that’s easy to use for beginners but provides many advanced features — including invoices, multisig wallets, cold storage, and a rich set of functionality for advanced users and developers.Most importantly, ElectrumG is very quick to load and very lightweight, consuming a lot less disk space than a full node wallet.How’s it so Lightweight?Unlike a “full node” wallet, ElectrumG on your computer doesn’t validate every BTG transaction and maintain a full copy of the BTG blockchain, so it doesn’t need hundreds of gigabytes of space on your computer. Instead, it relies on lightweight block headers and uses SPV (Simplified Payment Verification, as described in the Bitcoin Whitepaper) to verify payments. Like any SPV wallet, ElectrumG relies on ElectrumX servers for some functions, such as receiving new block headers, or broadcasting new payments after they are signed — but the private keys used to sign those transactions never leave your computer. You remain in complete control of your private keys.Production vs BetaThe current production version, ElectrumG 3.2.1, was released just before the Network Upgrade hardfork. The wallet and back-end ElectrumX servers were upgraded to remain functional after the fork. This version does not include support for hardware wallets, which will be added in an upcoming Beta. (Hardware wallet support was initially planned for the 3.2.1 release, but needed to be delayed in favor of rolling out support for the Network Upgrade.)Free and Open Source!ElectrumG will continue to be free and open-source, with ongoing development and support provided by the Bitcoin Gold Organization. (See the full source code on GitHub.)The Bitcoin Gold Organization also hosts and maintains a globally distributed set of ElectrumX servers, which were upgraded for the Network Upgrade.We’d like to thank Spesmilo (Electrum) and Kyuupichan (ElectrumX) for their hard work on the Electrum projects over the years, as well everyone else in the Open Source Community that has contributed to the creation and growth of projects like these.We’ll continue to work hard to provide the kind of software users want, the services developers need, and to continue expanding and supporting the Bitcoin Gold Ecosystem.Working hard and making progress,The Bitcoin Gold Organization#1CPU1VOTEOriginally posted on the Bitcoin Gold website; discuss this article here or on our Forums.Where do I get it?ElectrumG 3.2.1Please report Issues on GitHub or the Forum.Feature ListBeyond a pleasant interface, ElectrumG provides users with a full suite of functions:seed recovery phrases, a secure system which is more user-friendly than hexadecimal codeswallet encryptionmulti-signature wallets, for cases where control of funds needs to be distributedeasy import of Bitcoin address or private keyscold storage — the ability to create and sign raw transactions offline and then broadcastinvoicing functionalityIn the near future, ElectrumG will also include:hardware wallet connectivity, so you can use ElectrumG while keeping your private keys on a hardware wallet like Trezor, Ledger, or KeepKeyFor developers, ElectrumG provides:a powerful command line interfaceability to use cold storage with the command linea GUI Python consolean ElectrumG daemon for scripted uses, such the ability to accept BTG on a website with signed payment requests

bitcoingold.org is Back Online

BITCOINGOLD.ORG is online and all systems are green.Some of our services (accessed through the bitcoingold.org name) were inaccessible to the public between 13:00 UTC on 21 June and 17:10 UTC on 23 June.A team member’s recent model mobile phone with up-to-date software and patches was remotely hacked using zero-day exploits. This was a sophisticated and targeted attack. The hackers were then able to hijack our account with our Domain Registrar and point our domain name away from our DNS servers, causing people to lose access to our website, forum, and any services using the bitcoingold.org name.Our DNS servers and infrastructure were never compromised.also…The BTG blockchain experienced no impact whatsoever.BTG mining and transactions continued normally. The blockchain does not depend on our infrastructure — it is a free-standing decentralized blockchain.Of interest to other coin development teams:Forensics suggests this was a planned and very sophisticated attack, likely timed to maximally disrupt our Network Upgrade.In addition to the usual security measures, such as ensuring that all devices are kept up-to-date, using secure passwords, never allowing passwords to be cached, and using 2FA, we wish to remind everyone of the following:external systems which can impact your infrastructure may need even more attention than your infrastructureseparate, secure emails for critical services are an administrative hassle but add an important layer of security in case accounts are compromisedmodern mobile phones are particular targets because they often connect to many email accounts and multiple servicesSMS-based 2FA is greatly inferior in security to air-gapped hardware 2FA devices — refrain from using systems that don’t allow better 2FA than SMS on mobile phonesGetting back to our normally scheduled work,The Bitcoin Gold Organization#1CPU1VOTEOfficial blogpost: https://bitcoingold.org/bitcoingold-org-is-back-online/

Bitcoin Gold Network Upgrade

Our Network Upgrade plans are progressing steadily, and the BTG blockchain continues to function normally.Countdown timer and full details hereOur Network Upgrade is scheduled for block height (536200), roughly July 1st, 2018.This Upgrade will be a hard fork, which simply means that software upgrades for full nodes and miners are mandatory. (No new coin will be created.)This Upgrade implements Equihash-BTG as our new PoW algorithm and deploys an improved Difficulty Adjustment Algorithm. No changes are made to the coin supply or the rate of coin creation (miner rewards.)Partners including Exchanges, Wallet Providers, Pool Operators, and Miners can find important details on our GitHub, here: Full Upgrade Specification / GuideOther resources on GitHub:Mining Tools for DevelopersBitcoin Gold Core Wallet (Full-Node)0.15.1-rc1The development team is prepared to assist our partners in preparing for the hardfork. Please don’t hesitate to contact us for help:DiscordTelegramEmail: support at bitcoingold.orgAlways moving forwards,The Bitcoin Gold Organization#1CPU1VOTE

Network Upgrade: Testnet To...

Mandatory Network UpgradeBitcoin Gold is in the process of a mandatory Network Upgrade. Executing this upgrade requires a hard fork, but we anticipate a smooth upgrade with no chain splits (and no new coins created.)We have successfully Upgraded the Testnet via hard fork. Our Partners and we are proceeding to finalize the necessary upgrades to related software and preparing for the upcoming Mainnet upgrade.Our target for the Mainnet Upgrade is block height 536200, which should hit sometime around July 1st, and is subject to change based on feedback from critical Partners in the Ecosystem.Technical Changes:Implement new PoW: Equihash-BTG“Equihash-BTG” is Equihash<144,5> with BTG-specific Personalization(Old PoW was “Equihash,” which is Equihash<200,9> with generic implementation)See https://bitcoingold.org/equihash-btg/ for more detail.2. Deliver improved Difficulty Adjustment AlgorithmNew DAA is LWMA with optimized parameters(Old DAA was Digishield v3 with inferior parameters)Goals:ASIC resistanceEquihash-BTG is dramatically more ASIC-resistant than the generic Equihash, rendering the recently-available Equihash ASICs ineffective for mining BTGEquihash-BTG will probably make future ASIC designs non-competitive for a significant period of time2. SafetyPoW & personalization changes create BTG-specific hashpower, and therefore a new “hashpower market segment” specific to BTGBTG will be the dominant coin in the Equihash-BTG hashpower market, increasing security against 51% attacksAlthough we expect Equihash-BTG rental markets to emerge quickly, they will be more transparent because there is only one practical use for Equihash-BTG hashpower. This means easier monitoring for potentially malicious activity.3. Consistency and RegularityNew DAA (Difficulty Adjustment Algorithm) delivers much better responsiveness to hashpower shifts (which happen due to changing market prices and hashpower market dynamics)This will smooth out block times, reducing the incidence of “fast” and “slow” periodsWill also increase average profitability for “steady miners” of BTGMining Software and PoolsThe first few Equihash-BTG capable miners for NVidia cards are already available, and we expect AMD-based miners to be available soon. We will begin maintaining a list of known compatible mining software and expected mining pool availability on the Forum as details become publicly available from the 3rd parties who make and maintain them.In ClosingWe’re very happy with the cooperation we’re getting from many of our Partners in the Ecosystem, but also from the community of Equihash-based coin teams with which we’ve been collaborating these past weeks. We know some wish this Upgrade could be delivered sooner, but coordinating with all our Partners and ensuring the mining infrastructure is ready are crucial to minimize disruption — and, of course, critical for safety.We look forward to sharing many additional details in the next few days!Improving every day,The Bitcoin Gold Organization#1CPU1VOTEThis content is also posted on our Project Website as well as on our Discourse Forum.

Equihash-BTG: Our New PoW A...

(originally published here: https://bitcoingold.org/equihash-btg/)Summary:Our current mining algorithm, Equihash, is used by many different coins without any personalization. It was originally developed by Zcash and based on the parameter set <200,9>. We are going to upgrade to Equihash with a the parameter set <144,5>, with some customization. We’ll call it “Equihash-BTG,” for now. This will keep our blockchain ASIC-resistant and add an immediate measure of safety from 51% attacks.About EquihashEquihash, which was first developed and used by Zcash, was designed from the outset to be an “ASIC-resistant” Proof of Work algorithm. The developers set out to accomplish this by making it a memory-hardalgorithm. (See the Biryukov and Khovratovich paper on Equihash.) What does this mean, how does it make mining ASIC-resistant?A memory-hard algorithm is one which requires a lot of memory to be able to run. It simply won’t work on hardware that doesn’t have enough memory.When making an ASIC — an Application-Specific Integrated Circuit — adding memory is very expensive, and the more memory you need, the more expensive it gets. With a high enough memory requirement, building a “single-chip solver” on an ASIC becomes so expensive that you could not hope to earn enough in mining to pay for the ASIC. It’s impossible to profit.Equihash was engineered to make that to happen — it can be configured to need a lot of memory as a minimum requirement to run, and it needs several times that much to run efficiently. (If you use half the ideal amount of memory, it can be 1000 times slower.)Exactly how much memory is required? That depends on a couple of parameters.The current Equihash: <200,9>Equihash is the name for the general algorithm, but the exact implementation depends on two parameters, < n, k >. Today’s common Equihash coins run on Equihash <200,9>, so n = 200 and k = 9. This setup is currently used interchangeably by Bitcoin Gold, Zcash, Zencash, and many other Equihash-based cryptos.This <200,9> version of Equihash requires a minimum of 50 MB of memory but can run much faster with 144 MB of memory. This was not the most demanding (most memory-hard) version of Equihash considered at the time, but it appeared to be “good enough.” These memory requirements were previously sufficient to prevent building an ASIC, based on the comparison of ASIC cost to coin value a year or two ago. Since then, Zcash — which was worth $30 in Feb of 2017 — has grown to be worth over $250, and now there are multiple coins that can be mined with the same Equihash. Meanwhile, the cost of transistors in an ASIC has gone down.With these changes, it became possible to build an ASIC that can work with just enough memory to profitably mine the current Equihash coins — and this is precisely what has come to pass. But this doesn’t mean that Equihash is defeated — just that Equihash <200,9>.Equihash-BTG: <144,5>We’ll be adopting different parameters, <144,5>, for Equihash-BTG. Although these numbers are smaller than <200,9>, it means the algorithm actually requires dramatically more memory to run — so much more that we believe ASICs will be impossibly unprofitable for quite some time. The <144,5> parameters require a minimum of 700 MB to run and use about 2.5 GB to run efficiently (that’s 17 times larger!) This should be too expensive to produce with an ASIC right now, while most graphics cards used by our miners already have that much memory or more.We’ve seen the innards of the Z9 Equihash miner, and we’re no longer concerned that it might be able to mine Equihash-BTG effectively. We’ve tested the new algorithm with typical graphics cards and have confirmed that they can run the new algorithm with as little as 3GB of RAM (although it can be a bit tricky under Windows if trying to mine while still using the computer.)The sheer amount of memory required for Equihash-BTG pretty much forces the use of DRAM, which calls for a dramatically different design than a single-chip solver for regular Equihash. Even if a specialty miner is developed for Equihash-BTG in the future, it will not have as dramatic an advantage over a GPU as the specialty Equihash <200,9> miners. This significantly decreases the threat ASICs can pose to our network. While we know that this parameter change is not a permanent fix — this one change won’t stop ASICs forever — we know it will solve the ASIC-resistance problem for now, and gives us time to consider other alternatives for the longer term, if necessary.The new parameters in Equihash-BTG also provide a few other advantages over <200,9>, which you can read about in our more detailed Forum post about Equihash-BTG.Enhanced SafetyThe new algorithm doesn’t just protect us from ASIC miners — it moves us into a different “pool” of hashpower, which also gives us a measure of safety against the kind of 51% attacks against Exchanges that happened over three or four days this past May.Why does the new algorithm make us safer? It has to do with the size of the pool of hashpower available as Equihash. The total supply of power is large because it’s currently used interchangeably by multiple coins, and some of those coins produce new coins quite liberally — they generate a lot of miner rewards, which attracts a lot of hashpower, making the total pool very big. Though the share of power available for rental may be a small fraction of the total power for all coins, it can be a large share compared to individual coins, such as Bitcoin Gold. When the power available to rent on demand is larger than the power mining our coin, our chain is potentially at risk of attack (if someone has the financial means to rent all of that hashpower while simultaneously having the resources to make an enormous double-spend attempt against an exchange.)Because Equihash-BTG is different from the existing pool of regular Equihash power, we’ll effectively be in a separate pool of power. This means BTG will dominate the hashrate on this new PoW algorithm, which is “personalized” to BTG, adding a layer of incompatibility versus other coins that will be moving to the <144,5> parameter set, such as BTCZ (we’ve been collaborating with many other coin teams in the space.)Timing and Future UpdatesWhile we’re very close to being able to provide Release Candidate versions of all the software to the public, we still aren’t ready to commit to a specific fork date. We’ll begin releasing detailed information about progress with the code and timing to all of our partners in the coming days to assist them in preparations. Because this kind of Network Upgrade will be enacted via Hard Fork, we need to be sure our partners are prepared. (A Hard Fork does not mean there will be a new coin — it just means that the prior software won’t be compatible, so the Upgrade is not optional.) Our ecosystem includes dozens of partners, including mining pools, miners, the makers of mining software, blockchain explorers, wallet hardware and software providers, third-party merchant services, and over fifty exchanges! We’re doing our utmost to ensure that everyone in our community has the opportunity to prepare so that nobody is left behind when the time of the Upgrade comes.Working towards a better future,The Bitcoin Gold Organization#1CPU1VOTEReferences:Biryukov and Khovratovich paper: Equihash: Asymmetric Proof-of-Work Based on the Generalized Birthday ProblemBlog Post: A Response to the ASIC ThreatForum Post: Our “New” Equihash: Equihash-BTGBlog Post: Responding to AttacksAdditional reference for 3rd-party miner developers:BTG Mining Tools GitHub Repository