Privacy & security - Samourai Wallet Adds Tor Integration in Privacy Push

robots

twitter:card

Samourai Wallet’s latest update supports Tor integration

twitter:description

Samourai Wallet Adds Tor Integration in Privacy Push - Bitcoin Magazine

twitter:title

https://admin.bitcoinmagazine.com/wp-content/uploads/2019/06/Project_-_Sketch_1_45.width-800.jpg

twitter:image

Privacy &amp; security

Dojo

Privacy

Samourai

Zerolink

bitcoin

connect

dojo

fact

full-node dojo

identity

information

integration

offering

personal

Samourai Wallet <a href="https://twitter.com/SamouraiWallet/status/1107715774045659136?s=19">announced</a> this month that its latest update supports <a href="https://en.bitcoin.it/wiki/Tor">Tor</a> integration, offering additional privacy for users.



<h4>What Does Tor Integration Enable?</h4>



In a conversation with Bitcoin Magazine, Samourai’s lead developer, who is known simply as “TD,” gave a rundown of the Tor integration. He explained that using the Tor integration before creating a new wallet can shield a user’s identity beyond the fact that they are not required to provide any personal information. With Tor, Samourai’s servers will not be able to see a user’s IP address when they connect to the API, only their Bitcoin addresses, thus protecting the one piece of information that could tie their wallet to their real-world identity.



He also noted that Tor-enabled connectivity paves the way for Samourai’s forthcoming Whirlpool mixing services and full-node Dojo offering, two more privacy-enhancing features.



“Our users have been requesting tighter Tor integration for some time,” TD explained. “It was a prerequisite for rolling out Whirlpool and Dojo.”



Whirlpool is Samourai’s implementation of <a href="https://github.com/Samourai-Wallet/Whirlpool">ZeroLink</a>, a coin-mixing protocol that has been anticipated <a href="https://medium.com/@nopara73/introducing-zerolink-the-bitcoin-fungibility-framework-dc5338086198">since 2017</a>. ZeroLink’s protocol demands the use of Tor, enabling Whirlpool to break chain analysis between incoming and outgoing coins. This shuffling helps to ensure privacy and further secure anonymity of the origin source of an outgoing transaction.



Samourai’s wallet-specific full node, Dojo, has been tailor-made to run over a Tor-only connection. This further establishes privacy, as the personal Dojo will include backend APIs that allow the Samourai Wallet to connect to the Dojo directly, bypassing the company’s own servers. The intent is to provide greater security and verification measures for users. The Samourai website claims that the full-node Dojo will sport an easy-to-use interface.



Samourai has also planned for a directory of PayNyms, a feature that provides users with stealth addresses to send transactions anonymously between other Samourai Wallet users.



<h4>Tor Has Its Issues</h4>



TD acknowledged that Tor integration could make for a slower network than others under certain conditions, though he suggested that “Tor users [would] readily accept that tradeoff.”



Other concerns relating to the Tor network might include the fact that it is blocked in certain locations and/or by certain internet service providers.



Regardless of its limitations, the privacy potential makes Tor essential to Samourai Wallet’s near future.



“Connectivity over Tor is now an integral part of Samourai Wallet and will be maintained in an important position within our code base as we move forward,” TD said.

Bitcoin Magazine provides news, analysis, information, commentary and price data about Bitcoin.

Bitcoin Magazine

Jimmy has been following the development of blockchain for several years, and he is optimistic about its potential to democratize the financial system.

Jimmy Aki

Samourai Wallet&#039;s latest update supports Tor integration, offering additional privacy for users and opening the door for more privacy-focused integrations.

Samourai Wallet Adds Tor Integration in Privacy Push

Samourai Wallet announced this month that its latest update supports Tor integration, offering additional privacy for users. What Does Tor Integration Enable? In a conversation with Bitcoin Magazine, Samourai&rsquo;s lead developer, who is known simply as &ldquo;TD,&rdquo; gave a rundown of the Tor integration. He explained that using the Tor integration before creating a new wallet can shield a user&rsquo;s identity beyond the fact that they are not required to provide any personal information. With Tor, Samourai&rsquo;s servers will not be able to see a user&rsquo;s IP address when they connect to the API, only their Bitcoin addresses, thus protecting the one piece of information that could tie their wallet to their real-world identity. He also noted that Tor-enabled connectivity paves the way for Samourai&rsquo;s forthcoming Whirlpool mixing services and full-node Dojo offering, two more privacy-enhancing features. &ldquo;Our users have been requesting tighter Tor integration for some time,&rdquo; TD explained. &ldquo;It was a prerequisite for rolling out Whirlpool and Dojo.&rdquo; Whirlpool is Samourai&rsquo;s implementation of ZeroLink, a coin-mixing protocol that has been anticipated since 2017. ZeroLink&rsquo;s protocol demands the use of Tor, enabling Whirlpool to break chain analysis between incoming and outgoing coins. This shuffling helps to ensure privacy and further secure anonymity of the origin source of an outgoing transaction. Samourai&rsquo;s wallet-specific full node, Dojo, has been tailor-made to run over a Tor-only connection. This further establishes privacy, as the personal Dojo will include backend APIs that allow the Samourai Wallet to connect to the Dojo directly, bypassing the company&rsquo;s own servers. The intent is to provide greater security and verification measures for users. The Samourai website claims that the full-node Dojo will sport an easy-to-use interface. Samourai has also planned for a directory of PayNyms, a feature that provides users with stealth addresses to send transactions anonymously between other Samourai Wallet users. Tor Has Its Issues TD acknowledged that Tor integration could make for a slower network than others under certain conditions, though he suggested that &ldquo;Tor users [would] readily accept that tradeoff.&rdquo; Other concerns relating to the Tor network might include the fact that it is blocked in certain locations and/or by certain internet service providers. Regardless of its limitations, the privacy potential makes Tor essential to Samourai Wallet&rsquo;s near future. &ldquo;Connectivity over Tor is now an integral part of Samourai Wallet and will be maintained in an important position within our code base as we move forward,&rdquo; TD said.

Samourai Wallet's latest update supports Tor integration, offering additional privacy for users and opening the door for more privacy-focused integrations.

description

max-snippet:-1, max-image-preview:large, max-video-preview:-1

Samourai Wallet Adds Tor Integration in Privacy Push - bitcoinmagazine.com

Adoption & community - Bitcoin Wallet Forced to Drop Key Privacy Features From Google Play App

The privacy restrictions on Samourai’s wallet will only affect the new version available on Google Play.

Bitcoin Wallet Forced to Drop Key Privacy Features From Google Play App - Bitcoin Magazine

https://admin.bitcoinmagazine.com/wp-content/uploads/2019/06/Samourai.width-800.jpg

Adoption &amp; Community

#bitcoin

Google

Google play

Wallet

blog post

commands and sim

commands and sim switch

commands and sim switch defense

google play

mode remote

privacy features

regarding sms and dialer

regarding sms and dialer permissions

samourai

Privacy-focused bitcoin wallet Samourai is having its hand forced by Google.



According to a Samourai blog post, the wallet provider is disabling privacy features that are key to its design before its latest version, 0.99.4, hits the Google Play store tomorrow. The removed features include Samourai’s Stealth Mode, remote text message (SMS) commands, and SIM Switch Defense (a measure to protect against sim swaps).



The privacy restrictions only affect the version of the wallet available on Google Play. To bypass these restrictions, users can also download what Samourai calls the “non-nerfed version” of the wallet client’s latest version directly from the project’s <a href="https://github.com/Samourai-Wallet/samourai-wallet-android/releases/tag/0.99.03">Github</a>. Down the road, the team also hopes to get the wallet, privacy features fully-enabled, listed on F-Droid and other alternative, open-source app stores, as well.



“In October, Google announced changes to their policies regarding SMS and Dialer permissions that apps are allowed to use. The way that our Stealth Mode, Remote SMS commands, and SIM Switch Defense work require use of these permissions,” a Samourai Wallet representative told Bitcoin Magazine in an email correspondence.



Samourai proceeded to file for an exemption, but they were notified of their exemption’s rejection just “a few days ago,” according to the representative.



“Unfortunately, they didn't tell us anything specifically, we learned of everything through automated emails that could not be responded to,” they continued.



Samourai is only available for Android, in part because it can’t pin down iOS developers who “are willing to work for the passion of it over the profit,” the representative indicated. The project hasn’t “had much luck with iOS developers so far,” but it is “committed to bringing some version of Samourai to the iOS store eventually,” they claimed.



With these restrictions, Samourai lamented the changing landscape of Android over the past few versions. These changes have, in Samourai’s words, created a “walled garden,” something the wallet provider discusses in its blog post and reiterated in our correspondence.



“Very strict changes in background data a few versions ago meant that Samourai users would no longer receive alerts on incoming payments unless we routed all alerts through Google’s own servers. We obviously decided not to do that, but that was — in our view — the beginnings of the walled garden being built. The latest policy changes regarding SMS and Dialer permissions show a marked change of strategy for Google, bringing it closer in alignment with the Apple iOS Store than ever before.”



If users opt to download the wallet directly from Samourai’s Github, the team cautioned that they should “verify the integrity of the APK they download by comparing the SHA-256 hash of their APK with the SHA-256 hash published on Github.”



At time of publication, Google had not responded to Bitcoin Magazine’s request for comment.

Colin is an associate editor and staff writer for Bitcoin Magazine. He&#39;s proud to call Nashville his home, where he lives with his family and doesn&#39;t eat hot chicken as much as you might think.

Colin Harper

The privacy restrictions on Samourai&#039;s wallet will only affect the new version available on Google Play.

Bitcoin Wallet Forced to Drop Key Privacy Features From Google Play App

Privacy-focused bitcoin wallet Samourai is having its hand forced by Google. According to a Samourai blog post, the wallet provider is disabling privacy features that are key to its design before its latest version, 0.99.4, hits the Google Play store tomorrow. The removed features include Samourai&rsquo;s Stealth Mode, remote text message (SMS) commands, and SIM Switch Defense (a measure to protect against sim swaps). The privacy restrictions only affect the version of the wallet available on Google Play. To bypass these restrictions, users can also download what Samourai calls the &ldquo;non-nerfed version&rdquo; of the wallet client&rsquo;s latest version directly from the project&rsquo;s Github. Down the road, the team also hopes to get the wallet, privacy features fully-enabled, listed on F-Droid and other alternative, open-source app stores, as well. &ldquo;In October, Google announced changes to their policies regarding SMS and Dialer permissions that apps are allowed to use. The way that our Stealth Mode, Remote SMS commands, and SIM Switch Defense work require use of these permissions,&rdquo; a Samourai Wallet representative told Bitcoin Magazine in an email correspondence. Samourai proceeded to file for an exemption, but they were notified of their exemption&rsquo;s rejection just &ldquo;a few days ago,&rdquo; according to the representative. &ldquo;Unfortunately, they didn&#039;t tell us anything specifically, we learned of everything through automated emails that could not be responded to,&rdquo; they continued. Samourai is only available for Android, in part because it can&rsquo;t pin down iOS developers who &ldquo;are willing to work for the passion of it over the profit,&rdquo; the representative indicated. The project hasn&rsquo;t &ldquo;had much luck with iOS developers so far,&rdquo; but it is &ldquo;committed to bringing some version of Samourai to the iOS store eventually,&rdquo; they claimed. With these restrictions, Samourai lamented the changing landscape of Android over the past few versions. These changes have, in Samourai&rsquo;s words, created a &ldquo;walled garden,&rdquo; something the wallet provider discusses in its blog post and reiterated in our correspondence. &ldquo;Very strict changes in background data a few versions ago meant that Samourai users would no longer receive alerts on incoming payments unless we routed all alerts through Google&rsquo;s own servers. We obviously decided not to do that, but that was &mdash; in our view &mdash; the beginnings of the walled garden being built. The latest policy changes regarding SMS and Dialer permissions show a marked change of strategy for Google, bringing it closer in alignment with the Apple iOS Store than ever before.&rdquo; If users opt to download the wallet directly from Samourai&rsquo;s Github, the team cautioned that they should &ldquo;verify the integrity of the APK they download by comparing the SHA-256 hash of their APK with the SHA-256 hash published on Github.&rdquo; At time of publication, Google had not responded to Bitcoin Magazine&rsquo;s request for comment.

The privacy restrictions on Samourai's wallet will only affect the new version available on Google Play.

Colin is an associate editor and staff writer for Bitcoin Magazine. He's proud to call Nashville his home, where he spends his days shouting at peddle taverns and trying to find affordable parking downtown. If it wasn't already obvious, he holds bitcoin.

Bitcoin Wallet Forced to Drop Key Privacy Features From Google Play App - bitcoinmagazine.com

twitter:creator

Privacy & security - Blockchain Analysis Is About to Get Harder as P2EP Enters Testing Phase

“Privacy is essential for Bitcoin. Ideally we want to screw up [blockchain] analysis so badly

Blockchain Analysis Is About to Get Harder as P2EP Enters Testing Phase - Bitcoin Magazine

https://admin.bitcoinmagazine.com/wp-content/uploads/2019/06/P2EP-privacy.width-800.jpg

Bustabit

Coinjoin

Havar

Maxwell

P2ep

0.3 btc

address clustering

belong to the same entity

bitcoin developers and privacy

bitcoin developers and privacy researchers

bitcoin magazine

blockchain analysis

brainstorming event

Yet another tool is being added to Bitcoin’s<a data-original-title="" href="https://bitcoinmagazine.com/articles/bitcoin-privacycoin-tech-making-bitcoin-more-private/"> growing number of privacy solutions</a>. 



Thought up at a brainstorming event attended by Bitcoin developers and privacy researchers last summer, Pay to Endpoint (P2EP) is a relatively new trick that utilizes the well-known CoinJoin mixing technique to make blockchain analysis much harder. An early version of it, called “Bustapay,” was quickly implemented by independent Bitcoin developer Ryan Havar and is being tested as of now. Meanwhile, the privacy-focused Samourai Wallet as well as JoinMarket developer Adam Gibson are working on two P2EP projects of their own, which are getting closer to deployment too.



“Privacy is essential for Bitcoin,” Havar told Bitcoin Magazine. “Ideally we want to screw up [blockchain] analysis so badly, that they can't even make it.”



<h4>CoinJoin</h4>



To understand P2EP, let’s first recap what CoinJoin transactions look like, and why they are (and aren’t) useful.



Many normal Bitcoin transactions send coins from several addresses (inputs), because the sender’s addresses individually don’t contain enough coins needed for the payment. This is very helpful for blockchain spies, as it usually means that all inputs in a transaction belong to the same entity. It allows for address clustering.



But by combining several transactions into one big transaction, CoinJoin — a privacy solution first proposed by Bitcoin Core contributor Gregory Maxwell — has the potential to break this assumption. If multiple senders cooperate to create a single transaction that sends coins from all of their inputs to the different receiving addresses (outputs) they’re paying, blockchain spies would be wrong to assume all inputs belong to the same entity. As such, they can’t just assume it, even if it is a regular transaction. It would make address clustering, and thus blockchain analysis, significantly harder.



However, CoinJoin also has its limitations. If all CoinJoin participants don’t use equal amounts, it’s easy to puzzle together which inputs are paying which outputs. As such, it doesn’t really prevent address clustering after all.



CoinJoin is still useful for mixing, which can easily be done with equal amounts. Users don’t pay other users, but rather, themselves. This is effective in breaking the trail of coins, but it does give away that a mixing session took place.



“While it ‘clears your history,’ it is not as useful as people imagine,” Havar argued. “Your coins are obviously and intentionally washed. That makes it problematic to use. Try depositing your post-mixed coins into an exchange, for example, and watch when they lock your account and ask you a lot of questions.”



CoinJoin’s potential to break the assumptions used for addresses clustering had not really been realized yet. But this may be about to change.



<h4>P2EP</h4>



P2EP is a relatively new idea, first proposed by participants of a brainstorming event for Bitcoin developers and privacy researchers last summer, who published the idea in<a href="https://medium.com/@nopara73/pay-to-endpoint-56eb05d3cac6"> several</a><a href="https://blockstream.com/2018/08/08/improving-privacy-using-pay-to-endpoint/"> blogs</a>. It cleverly works around CoinJoin’s “equal amount” limitation, opening up the possibility to use CoinJoin for regular payments — not just mixing specifically.



The central concept behind P2EP is simple yet effective: the receiving party in a payment takes part in the CoinJoin. If Alice pays Bob, Bob participates in Alice’s CoinJoin transaction to him, so he also pays himself.



Say, for example, that Alice wants to send Bob 1.2 BTC. She may send it from two inputs: one that contains 1 BTC and one that contains 0.5 BTC. This adds up to 1.5 BTC, which means she also sends 0.3 BTC back to herself as change in the same transaction.



With P2EP, Bob adds one input of his own in the mix: let’s say it contains 0.9 BTC. As such, the transaction now has three inputs worth 1, 0.9 and 0.5 BTC, for a total of 2.4 BTC. The transaction also has two receiving addresses, worth 2.1 and 0.3 BTC. The 0.3 BTC is still the same change going back to Alice, while the 2.1 BTC really consist of the original payment of 1.2, plus the 0.9 that Bob is sending himself. While the transaction has some padding, Alice still just paid a total of 1.2 BTC to Bob.



Importantly, not all inputs in this transaction belong to Alice, and it’s no longer obvious that a CoinJoin took place: there are no matching “sending” and “receiving” amounts to link addresses together.



<blockquote class="wp-block-quote">“The on-chain structure of a P2EP payment is exactly like a normal transaction. So, at certain points, spies know their analysis is corrupted, but they don't exactly know how. Ideally, we want to screw up the analysis so badly, that they can't even make it,” said Havar.</blockquote>



<h4>Bustapay</h4>



Havar is the previous owner of <a data-original-title="" href="http://bustabit.com/">Bustabit</a>, an online gambling game, and has plenty of experience in the Bitcoin casino space in general. This is how he got a firsthand taste of Bitcoin’s privacy and fungibility issues: Several exchanges blacklist coins that are associated with gambling sites.



“As a casino operator, you want to help protect the privacy of your players,” Havar explained. “So I implemented a huge amount of privacy oriented features, but each time I was kind of surprised how ineffective it was. Bitcoin truly leaks a lot more information than you'd expect.”



Havar sold Bustabit earlier this year and got interested in P2EP when he read about it last summer. He got to work and first<a href="https://www.mail-archive.com/bitcoin-dev@lists.linuxfoundation.org/msg07386.html"> announced</a> the Bustapay implementation in late August 2018: a basic version of P2EP.



While intentionally keeping it simple, Havar believes he has improved on initial P2EP proposals in particular when it comes to denial-of-service prevention (where someone indicates an intention to make a payment but doesn’t) and privacy (spies can use the denial-of-service trick to learn which addresses belong to the payee). In both cases, Havar’s solution lets the payee claim a regular payment if the payer bails on the P2EP payment. This makes the attacks expensive — perhaps too expensive to be worthwhile.



Havar hopes the implementation will be adopted by wallets and services, but he did note interest has been limited so far.



“I tried to reach out to most wallets — but there's largely apathy,” Havar said, realizing Bustapay suffers from a “chicken-and-egg” problem. “For any wallet developer, there's a million things to do, and who wants to implement a protocol no one supports? Meanwhile, when I talk to several big bitcoin businesses, no one wanted to implement a protocol that no wallets support.”



Still, one service has now implemented Bustapay: Bustabit, the casino game Havar used to own, and which he himself believes might even be the biggest one on the internet. To keep things moving forward, Havar put out a<a data-original-title="" href="https://old.reddit.com/r/Bitcoin/comments/a8xqwk/call_for_testing_bustapay_a_practical_coinjoin/"> call for testers</a> and even offered a small reward last week, while also<a href="https://bitcointalk.org/index.php?topic=279249.msg48881217#msg48881217"> proposing</a> wallet developers should get a piece of a five-year-old “<a href="https://bitcointalk.org/index.php?topic=279249.msg2983911#msg2983911">CoinJoin bounty fund</a>.”



With these tests, Havar hopes to learn how effective the implementation really is.



“Someone with Chainalysis access is giving me information about its effectiveness,” he told Bitcoin Magazine, “so I can kind of see how well it works, and how confused it gets.”



<h4>Stowaway and Payjoin</h4>



It turns out Bustapay is not the only P2EP project.



Inspired by a much earlier<a href="https://bitcointalk.org/index.php?topic=139581.0"> idea</a> by Maxwell to disrupt blockchain analysis, privacy-focused Samourai Wallet<a href="https://twitter.com/SamouraiDev/status/1041060386810875904"> revealed</a> in September it has been working on a P2EP-type of solution, too. Based on<a href="https://gist.github.com/LaurentMT/e758767ca4038ac40aaf"> guidelines</a> by data analyst LaurentMT, the wallet had started working on the solution even before last summer's privacy brainstorming event and has been running<a href="https://twitter.com/SamouraiWallet/status/1078604277726224384"> private tests</a> since. Dubbed “Stowaway,” the feature will enter a public testnet phase within weeks.



Samourai Wallet’s implementation does have one big difference from Havar’s implementation, however, and will, therefore, be incompatible. 



“I'm happy to see Bustapay move forward, but personally I'm a bit put off by the the lack of ‘permissions’: It grants anyone the right to obtain knowledge about part of my UTXO [Bitcoin address] set,” pseudonymous Samourai Wallet developer “Samouraidev” told Bitcoin Magazine.



Stowaway will, therefore, only work between Samourai Wallet users that have indicated through the application that they have a trust relationship with each other.



“Users have to ‘follow’ one another and, in addition to that, provide that extra ‘permission’ to allow their UTXO set to be exposed,” said Samouraidev. “For example, I might have a basic two-way relation with my employer to receive [a] salary, but I do not want my employer to solicit me for collaborative spends, which would expose my UTXO set to him.”



And just a couple of days ago, a third P2EP project was revealed. Privacy-focused Bitcoin developer Adam Gibson is implementing a solution called “Payjoin” for another CoinJoin-based privacy project: JoinMarket.



Like Stowaway, Payjoin is specifically designed to be used between users’ wallets. Where Bustapay is developed with online merchants in mind and is available for anyone that wishes to make a payment, Payjoin would only be used when two users specifically choose to do so. 



“With Payjoin you're not passively waiting for arbitrary people to ping your server, so you don't have to worry about snooping attacks,” Gibson explained. “You exchange payment details and you end up with a transaction that looks like an ordinary payment.”



Having been part of the brainstorming session where P2EP was formalized, Gibson has been aware of the solution for a little while; in August, he was even among the first to explain it publicly in a<a href="https://youtu.be/0-DS7X99F7Y"> podcast</a>. But he said he’d only recently realized the full potential benefit of the trick. Besides privacy, P2EP also positively impacts Bitcoin’s UTXO set, as more unspent coins end up held by fewer addresses.



Gibson, therefore, started working on PayJoin about a week ago and said that implementing it is relatively easy, as JoinMarket wallets already communicate with one another anyway. He thinks he could have a working implementation ready to be integrated into JoinMarket within a few weeks.



“I initially kind of dismissed this idea offhand as not getting enough usage,” he said. “That's, of course, still likely true. But the main reason I decided to devote a bit of time to it in JoinMarket is everything is set up for that already: anonymised Tor connections between counterparties, encrypted messaging, etcetera. So, even if hardly anybody uses it, it acts as a showcase for other wallets and systems in Bitcoin to let them think about it.”



Photo by <a href="https://unsplash.com/photos/nxDNlB5Eves?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText">Patrick Fore</a> on <a data-original-title="" href="https://unsplash.com/search/photos/lottery-balls?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText">Unsplash</a>

Aaron van Wirdum is interested in decentralized consensus, FOSS, privacy in the digital age, censorship resistant payments, and more of that stereotypical Bitcoin stuff. Hodls BTC. (tip address / tippin.me / PayNym)

Aaron van Wirdum

&ldquo;Privacy is essential for Bitcoin. Ideally we want to screw up [blockchain] analysis so badly, that they can&#039;t even make it.&rdquo;

Blockchain Analysis Is About to Get Harder as P2EP Enters Testing Phase

Yet another tool is being added to Bitcoin&rsquo;s growing number of privacy solutions. Thought up at a brainstorming event attended by Bitcoin developers and privacy researchers last summer, Pay to Endpoint (P2EP) is a relatively new trick that utilizes the well-known CoinJoin mixing technique to make blockchain analysis much harder. An early version of it, called &ldquo;Bustapay,&rdquo; was quickly implemented by independent Bitcoin developer Ryan Havar and is being tested as of now. Meanwhile, the privacy-focused Samourai Wallet as well as JoinMarket developer Adam Gibson are working on two P2EP projects of their own, which are getting closer to deployment too. &ldquo;Privacy is essential for Bitcoin,&rdquo; Havar told Bitcoin Magazine. &ldquo;Ideally we want to screw up [blockchain] analysis so badly, that they can&#039;t even make it.&rdquo; CoinJoin. To understand P2EP, let&rsquo;s first recap what CoinJoin transactions look like, and why they are (and aren&rsquo;t) useful. Many normal Bitcoin transactions send coins from several addresses (inputs), because the sender&rsquo;s addresses individually don&rsquo;t contain enough coins needed for the payment. This is very helpful for blockchain spies, as it usually means that all inputs in a transaction belong to the same entity. It allows for address clustering. But by combining several transactions into one big transaction, CoinJoin &mdash; a privacy solution first proposed by Bitcoin Core contributor Gregory Maxwell &mdash; has the potential to break this assumption. If multiple senders cooperate to create a single transaction that sends coins from all of their inputs to the different receiving addresses (outputs) they&rsquo;re paying, blockchain spies would be wrong to assume all inputs belong to the same entity. As such, they can&rsquo;t just assume it, even if it is a regular transaction. It would make address clustering, and thus blockchain analysis, significantly harder. However, CoinJoin also has its limitations. If all CoinJoin participants don&rsquo;t use equal amounts, it&rsquo;s easy to puzzle together which inputs are paying which outputs. As such, it doesn&rsquo;t really prevent address clustering after all. CoinJoin is still useful for mixing, which can easily be done with equal amounts. Users don&rsquo;t pay other users, but rather, themselves. This is effective in breaking the trail of coins, but it does give away that a mixing session took place. &ldquo;While it &lsquo;clears your history,&rsquo; it is not as useful as people imagine,&rdquo; Havar argued. &ldquo;Your coins are obviously and intentionally washed. That makes it problematic to use. Try depositing your post-mixed coins into an exchange, for example, and watch when they lock your account and ask you a lot of questions.&rdquo; CoinJoin&rsquo;s potential to break the assumptions used for addresses clustering had not really been realized yet. But this may be about to change. P2EP. P2EP is a relatively new idea, first proposed by participants of a brainstorming event for Bitcoin developers and privacy researchers last summer, who published the idea in several blogs. It cleverly works around CoinJoin&rsquo;s &ldquo;equal amount&rdquo; limitation, opening up the possibility to use CoinJoin for regular payments &mdash; not just mixing specifically. The central concept behind P2EP is simple yet effective: the receiving party in a payment takes part in the CoinJoin. If Alice pays Bob, Bob participates in Alice&rsquo;s CoinJoin transaction to him, so he also pays himself. Say, for example, that Alice wants to send Bob 1.2 BTC. She may send it from two inputs: one that contains 1 BTC and one that contains 0.5 BTC. This adds up to 1.5 BTC, which means she also sends 0.3 BTC back to herself as change in the same transaction. With P2EP, Bob adds one input of his own in the mix: let&rsquo;s say it contains 0.9 BTC. As such, the transaction now has three inputs worth 1, 0.9 and 0.5 BTC, for a total of 2.4 BTC. The transaction also has two receiving addresses, worth 2.1 and 0.3 BTC. The 0.3 BTC is still the same change going back to Alice, while the 2.1 BTC really consist of the original payment of 1.2, plus the 0.9 that Bob is sending himself. While the transaction has some padding, Alice still just paid a total of 1.2 BTC to Bob. Importantly, not all inputs in this transaction belong to Alice, and it&rsquo;s no longer obvious that a CoinJoin took place: there are no matching &ldquo;sending&rdquo; and &ldquo;receiving&rdquo; amounts to link addresses together. &ldquo;The on-chain structure of a P2EP payment is exactly like a normal transaction. So, at certain points, spies know their analysis is corrupted, but they don&#039;t exactly know how. Ideally, we want to screw up the analysis so badly, that they can&#039;t even make it,&rdquo; said Havar. Bustapay. Havar is the previous owner of Bustabit, an online gambling game, and has plenty of experience in the Bitcoin casino space in general. This is how he got a firsthand taste of Bitcoin&rsquo;s privacy and fungibility issues: Several exchanges blacklist coins that are associated with gambling sites. &ldquo;As a casino operator, you want to help protect the privacy of your players,&rdquo; Havar explained. &ldquo;So I implemented a huge amount of privacy oriented features, but each time I was kind of surprised how ineffective it was. Bitcoin truly leaks a lot more information than you&#039;d expect.&rdquo; Havar sold Bustabit earlier this year and got interested in P2EP when he read about it last summer. He got to work and first announced the Bustapay implementation in late August 2018: a basic version of P2EP. While intentionally keeping it simple, Havar believes he has improved on initial P2EP proposals in particular when it comes to denial-of-service prevention (where someone indicates an intention to make a payment but doesn&rsquo;t) and privacy (spies can use the denial-of-service trick to learn which addresses belong to the payee). In both cases, Havar&rsquo;s solution lets the payee claim a regular payment if the payer bails on the P2EP payment. This makes the attacks expensive &mdash; perhaps too expensive to be worthwhile. Havar hopes the implementation will be adopted by wallets and services, but he did note interest has been limited so far. &ldquo;I tried to reach out to most wallets &mdash; but there&#039;s largely apathy,&rdquo; Havar said, realizing Bustapay suffers from a &ldquo;chicken-and-egg&rdquo; problem. &ldquo;For any wallet developer, there&#039;s a million things to do, and who wants to implement a protocol no one supports? Meanwhile, when I talk to several big bitcoin businesses, no one wanted to implement a protocol that no wallets support.&rdquo; Still, one service has now implemented Bustapay: Bustabit, the casino game Havar used to own, and which he himself believes might even be the biggest one on the internet. To keep things moving forward, Havar put out a call for testers and even offered a small reward last week, while also proposing wallet developers should get a piece of a five-year-old &ldquo;CoinJoin bounty fund.&rdquo; With these tests, Havar hopes to learn how effective the implementation really is. &ldquo;Someone with Chainalysis access is giving me information about its effectiveness,&rdquo; he told Bitcoin Magazine, &ldquo;so I can kind of see how well it works, and how confused it gets.&rdquo; Stowaway and Payjoin. It turns out Bustapay is not the only P2EP project. Inspired by a much earlier idea by Maxwell to disrupt blockchain analysis, privacy-focused Samourai Wallet revealed in September it has been working on a P2EP-type of solution, too. Based on guidelines by data analyst LaurentMT, the wallet had started working on the solution even before last summer&#039;s privacy brainstorming event and has been running private tests since. Dubbed &ldquo;Stowaway,&rdquo; the feature will enter a public testnet phase within weeks. Samourai Wallet&rsquo;s implementation does have one big difference from Havar&rsquo;s implementation, however, and will, therefore, be incompatible. &ldquo;I&#039;m happy to see Bustapay move forward, but personally I&#039;m a bit put off by the the lack of &lsquo;permissions&rsquo;: It grants anyone the right to obtain knowledge about part of my UTXO [Bitcoin address] set,&rdquo; pseudonymous Samourai Wallet developer &ldquo;Samouraidev&rdquo; told Bitcoin Magazine. Stowaway will, therefore, only work between Samourai Wallet users that have indicated through the application that they have a trust relationship with each other. &ldquo;Users have to &lsquo;follow&rsquo; one another and, in addition to that, provide that extra &lsquo;permission&rsquo; to allow their UTXO set to be exposed,&rdquo; said Samouraidev. &ldquo;For example, I might have a basic two-way relation with my employer to receive [a] salary, but I do not want my employer to solicit me for collaborative spends, which would expose my UTXO set to him.&rdquo; And just a couple of days ago, a third P2EP project was revealed. Privacy-focused Bitcoin developer Adam Gibson is implementing a solution called &ldquo;Payjoin&rdquo; for another CoinJoin-based privacy project: JoinMarket. Like Stowaway, Payjoin is specifically designed to be used between users&rsquo; wallets. Where Bustapay is developed with online merchants in mind and is available for anyone that wishes to make a payment, Payjoin would only be used when two users specifically choose to do so. &ldquo;With Payjoin you&#039;re not passively waiting for arbitrary people to ping your server, so you don&#039;t have to worry about snooping attacks,&rdquo; Gibson explained. &ldquo;You exchange payment details and you end up with a transaction that looks like an ordinary payment.&rdquo; Having been part of the brainstorming session where P2EP was formalized, Gibson has been aware of the solution for a little while; in August, he was even among the first to explain it publicly in a podcast. But he said he&rsquo;d only recently realized the full potential benefit of the trick. Besides privacy, P2EP also positively impacts Bitcoin&rsquo;s UTXO set, as more unspent coins end up held by fewer addresses. Gibson, therefore, started working on PayJoin about a week ago and said that implementing it is relatively easy, as JoinMarket wallets already communicate with one another anyway. He thinks he could have a working implementation ready to be integrated into JoinMarket within a few weeks. &ldquo;I initially kind of dismissed this idea offhand as...

“Privacy is essential for Bitcoin. Ideally we want to screw up [blockchain] analysis so badly, that they can't even make it.”

Aaron van Wirdum is interested in technology and how it affects social and political structures. He has been covering Bitcoin since 2013, focusing on privacy, scalability and more. Hodls BTC.

“Privacy is essential for Bitcoin. Ideally we want to screw up [blockchain] analysis so badly, that they can&#039;t even make it.”

Blockchain Analysis Is About to Get Harder as P2EP Enters Testing Phase - bitcoinmagazine.com

The best of Bitcoin Magazine’s cryptocurrency and blockchain stories from the week.

Week in Review for February 23 - Bitcoin Magazine

https://admin.bitcoinmagazine.com/wp-content/uploads/2019/06/bitcoin-magazine-week-in-review3.width-800.jpg

Review

Finhub

Gotenna

Regulation

Stablecoins

Tether

coin

companies

developers

exchanges

finhub

fintech

huobi and okex

markets

news

With the exception of the SEC’s FinHub announcement, it has been a quiet week for regulatory news — something we’ve been getting a lot of recently as U.S. officials <a href="https://bitcoinmagazine.com/articles/two-one-sec-slaps-crypto-hedge-fund-broker-registration-failures/">clamp down</a> on <a href="https://bitcoinmagazine.com/articles/federal-judge-applies-long-established-securities-law-icos/">unscrupulous coin offerings</a> and crypto companies. 



Instead, stablecoins crowded headlines this week, as tether — among others — had difficulties retaining its peg, and top exchanges rolled out support for some of the asset class’ regulatory-compliant newcomers.



All the while, developers remind us that, even in bear markets, the tools of innovation continue to work against the buzz of speculation.



<h4>Stablecoin News Takes Center Stage </h4>



<h5><a href="https://bitcoinmagazine.com/articles/tethers-peg-slips-bitcoin-price-distorted-across-market/">As Tether’s Peg Slips, Bitcoin’s Price Distorted Across Markets</a></h5>



Tether took a dip this week. The market’s leading stablecoin dropped to as low as $0.92 cents for its exchange-averaged price as a market-wide selloff left the coin wanting in demand. By consequence, bitcoin on tether-supported exchanges began trading at somewhat of a premium, an inflated price that reflected bitcoin’s worth against tether’s discounted price rather than its worth against the actual dollar. At the time of writing, tether has shaved off roughly $800 million from its market cap over the week — that’s nearly a third of its entire value.



<h5><a href="https://bitcoinmagazine.com/articles/huobi-joins-okex-adds-four-new-stablecoins/">Huobi </a>and <a href="https://bitcoinmagazine.com/articles/okex-lists-four-new-stablecoins/">OKEx </a>List the Same Four Stablecoins</h5>



As tether was unravelling, two of the industry’s highest volume exchanges listed four of the top stablecoins’ staunches competitors. Huobi and OKEx both announced support for TrueUSD, Gemini USD, USD Coin and the Paxos Standard earlier this week, moves that may have aggravated the sell off that crippled tether’s peg. The four stablecoins, which are fiat-collateralized like tether, are considered transparent, regulator-friendly alternatives to what was the market’s only viable stablecoin <a href="https://bitcoinmagazine.com/articles/search-stability-overview-budding-stablecoin-ecosystem/">until this year</a>.



<h4>Developers Keep On Developing </h4>



<h5><a href="https://bitcoinmagazine.com/articles/no-connection-required-how-one-dev-sent-bitcoin-while-grid/">No Connection Required: How One Dev Sent Bitcoin While Off the Grid</a></h5>



An Auckland developer sent bitcoin to his girlfriend earlier this week without access to internet — seriously. Leveraging technology developed by goTenna and Samourai Wallet, the Kiwi dev was able to transfer bitcoin across New Zealand using only a $27 smartphone and some impressive mesh network architecturing. 



<h5><a href="https://bitcoinmagazine.com/articles/decentralization-gains-traction-go-ethereum-fifth-most-active-github/">Decentralization Gains Traction: Go-Ethereum Fifth Most Active on GitHub</a></h5>



Commonly referred to as geth, Go-Ethereum, a command-line interface for running an Ethereum node using the Go programming language, is now the fifth fastest-growing, open-source project on GitHub. This puts it in the company of other, more mainstream projects like azure-docs from Microsoft Azure, pytorch from Facebook, godot from the GoDot Gaming Engine and nuxt.js, a Javascript framework.



<h4>SEC Opens a Pipeline for FinTech Companies to Seek Guidance</h4>



<h5><a href="https://bitcoinmagazine.com/articles/sec-sets-open-line-communication-f-projects-finhub/">SEC Sets Up Open Line of Communication for Fintech Projects With FinHub</a></h5>



On October 18, 2018, the U.S. Securities and Exchange Commission (SEC) announced that it has created a new offices dedicated to fintech startups, including cryptocurrency and blockchain companies. The office will be a resource for these fledging organizations as the try to navigate unspecified regulations and comply with government mandates.

The top bitcoin, cryptocurrency and blockchain news stories this week from Bitcoin Magazine

Bitcoin Magazine Week in Review: Stablecoins Take the Spotlight

With the exception of the SEC&rsquo;s FinHub announcement, it has been a quiet week for regulatory news &mdash; something we&rsquo;ve been getting a lot of recently as U.S. officials clamp down on unscrupulous coin offerings and crypto companies. Instead, stablecoins crowded headlines this week, as tether &mdash; among others &mdash; had difficulties retaining its peg, and top exchanges rolled out support for some of the asset class&rsquo; regulatory-compliant newcomers. All the while, developers remind us that, even in bear markets, the tools of innovation continue to work against the buzz of speculation. Stablecoin News Takes Center Stage As Tether&rsquo;s Peg Slips, Bitcoin&rsquo;s Price Distorted Across Markets Tether took a dip this week. The market&rsquo;s leading stablecoin dropped to as low as $0.92 cents for its exchange-averaged price as a market-wide selloff left the coin wanting in demand. By consequence, bitcoin on tether-supported exchanges began trading at somewhat of a premium, an inflated price that reflected bitcoin&rsquo;s worth against tether&rsquo;s discounted price rather than its worth against the actual dollar. At the time of writing, tether has shaved off roughly $800 million from its market cap over the week &mdash; that&rsquo;s nearly a third of its entire value. Huobi and OKEx List the Same Four Stablecoins. As tether was unravelling, two of the industry&rsquo;s highest volume exchanges listed four of the top stablecoins&rsquo; staunches competitors. Huobi and OKEx both announced support for TrueUSD, Gemini USD, USD Coin and the Paxos Standard earlier this week, moves that may have aggravated the sell off that crippled tether&rsquo;s peg. The four stablecoins, which are fiat-collateralized like tether, are considered transparent, regulator-friendly alternatives to what was the market&rsquo;s only viable stablecoin until this year. Developers Keep On Developing No Connection Required: How One Dev Sent Bitcoin While Off the Grid An Auckland developer sent bitcoin to his girlfriend earlier this week without access to internet &mdash; seriously. Leveraging technology developed by goTenna and Samourai Wallet, the Kiwi dev was able to transfer bitcoin across New Zealand using only a $27 smartphone and some impressive mesh network architecturing. Decentralization Gains Traction: Go-Ethereum Fifth Most Active on GitHub Commonly referred to as geth, Go-Ethereum, a command-line interface for running an Ethereum node using the Go programming language, is now the fifth fastest-growing, open-source project on GitHub. This puts it in the company of other, more mainstream projects like azure-docs from Microsoft Azure, pytorch from Facebook, godot from the GoDot Gaming Engine and nuxt.js, a Javascript framework. SEC Opens a Pipeline for FinTech Companies to Seek Guidance. SEC Sets Up Open Line of Communication for Fintech Projects With FinHub On October 18, 2018, the U.S. Securities and Exchange Commission (SEC) announced that it has created a new offices dedicated to fintech startups, including cryptocurrency and blockchain companies. The office will be a resource for these fledging organizations as the try to navigate unspecified regulations and comply with government mandates.

Bitcoin Magazine Week in Review: Stablecoins Take the Spotlight - bitcoinmagazine.com

Adoption & community - No Connection Required: How One Dev Sent Bitcoin While Off the Grid

No Connection Required: How One Dev Sent Bitcoin While Off the Grid - Bitcoin Magazine

https://admin.bitcoinmagazine.com/wp-content/uploads/2019/06/tenna_test.width-800.jpg

Transaction

bitcoin transaction

blockchain

developer

experiment

gotenna

huge

internet

internet connection

network

Following a <a data-original-title="" href="https://bitcoinmagazine.com/articles/samourai-and-gotenna-enable-bitcoin-transactions-without-internet-access/">partnership</a> between Samourai Wallet and goTenna, which now allows users to send bitcoin transactions offline, one <a data-original-title="" href="https://twitter.com/Coinsurenz/">developer</a> in New Zealand is staying ahead of the curve.



Detailing the feat in a <a data-original-title="" href="https://twitter.com/Coinsurenz/status/1052022462790033408">series of tweets</a>, Rigel Walshe used a $27 entry level, Android smartphone and four goTennas (portable devices used to create off-grid radio signals) to successfully send a bitcoin transaction without access to the internet.







<blockquote class="wp-block-quote">



Over the weekend I sent a bitcoin transaction to a relay 12.6km away with no cell network or internet connection. Here&#39;s a tweetstorm about how I used <a href="https://twitter.com/gotenna?ref_src=twsrc{601460017d3bc413ee2c01992dc3bbfcc5cd14befb5c1a38cf5aee65dd179563}5Etfw">@gotenna</a> and <a href="https://twitter.com/SamouraiWallet?ref_src=twsrc{601460017d3bc413ee2c01992dc3bbfcc5cd14befb5c1a38cf5aee65dd179563}5Etfw">@SamouraiWallet</a> to do it



— Coinsure (@Coinsurenz) <a href="https://twitter.com/Coinsurenz/status/1052022462790033408?ref_src=twsrc{601460017d3bc413ee2c01992dc3bbfcc5cd14befb5c1a38cf5aee65dd179563}5Etfw">October 16, 2018</a></blockquote>



<script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>







 



Here’s how he did it.



Working in Auckland, New Zealand, Walshe used Google Maps to devise a relay route that would respect goTenna’s stated maximum relay range of 6.4 km (though he notes this region is mountainous, so it was important to find high ground so as to not have any land structures interfere with the signals).



As Walshe set up each goTenna, which has a concealed relay station, he sent a transaction to see if it effectively went through. His girlfriend was waiting on the other side of each transaction, with her smartphone connected to the goTenna mesh network Walshe created. (Although an internet connection was not needed in order to receive the transaction, she was only able to confirm that the transaction was successful by checking the blockchain over the internet.)



The developer was able to send a transaction from two of the three locations he used, citing that the third didn’t go through because it was “pushing the distance” of the goTennas.



A huge takeaway for Walshe was that, from the offline device, there was no way to know if the transaction had been received by the other party. Therefore, he would need to essentially depend upon the party on the other side, in this case his girlfriend, to accurately report back to him whether or not she had received the transaction. He noted that an analog message confirming that a successful transaction had taken place would be a huge advantage to the network.



“If this was being used in a disaster scenario ... after Hurricane Katrina, or in a hostile environment such as a prison or warzone, people may not be able to communicate to confirm the payment has actually made it onto the blockchain, as goTenna is a passive receiver system. A confirmation message would help reduce additional risk for those unable to use a solution like the Blockstream satellite for confirmation.”



<h4>So What?</h4>



While the experiment can be considered a success, off-grid transactions still have a long road ahead of them before they see mainstream adoption and application. Walshe’s own transactions were cumbersome enough, requiring that he set up specific hardware and map out a grid with multiple antennae to relay the transactions.



Nonetheless, the ability to begin to experiment with possible offline solutions is a huge plus for the Bitcoin community as a whole. As Walshe notes, “the requirement for internet access has been an objection point for bitcoin detractors since it started.”



Developments like this are important for Bitcoin, as it shows the technology being used in creative ways that are just beginning to push the boundaries of what we thought was possible.



When asked how he sees the results of his experiment used in the future, Walshe said to Bitcoin Magazine, “Hopefully other people will pick up the gauntlet and try to beat my record.” Indeed, we have seen blockchain technology make improvements in strides by first implementing ideas in the <a href="https://bitcoinmagazine.com/articles/how-hackathon-birthed-cryptokitties-origin-story1/">form of a game</a> in the past.



A challenging, time-costly game at best, the infrastructure setup was the hardest part of the experiment, according to Walshe. Despite the difficulties, however, he still points out that he’s “going to do a few more reports using some interesting terrain.”



Walshe welcomes other Bitcoin enthusiasts to try to top him. “There [are] some amazing things that could be done by combining goTenna and drones,” he said. “Let’s see what everyone can come up with.”

Michael is an associate at BTC Media who is passionate about the rise of Bitcoin and the downfall of the largest fiscal experiment in human history.

Michael Taiberg

Using a $27 entry level, Android smartphone and four goTennas, Rigel Walshe successfully sent a bitcoin transaction without access to the internet.

No Connection Required: How One Dev Sent Bitcoin While Off the Grid

Following a partnership between Samourai Wallet and goTenna, which now allows users to send bitcoin transactions offline, one developer in New Zealand is staying ahead of the curve. Detailing the feat in a series of tweets, Rigel Walshe used a $27 entry level, Android smartphone and four goTennas (portable devices used to create off-grid radio signals) to successfully send a bitcoin transaction without access to the internet. Over the weekend I sent a bitcoin transaction to a relay 12.6km away with no cell network or internet connection. Here&#039;s a tweetstorm about how I used @gotenna and @SamouraiWallet to do it &mdash; Coinsure (@Coinsurenz) October 16, 2018 Here&rsquo;s how he did it. Working in Auckland, New Zealand, Walshe used Google Maps to devise a relay route that would respect goTenna&rsquo;s stated maximum relay range of 6.4 km (though he notes this region is mountainous, so it was important to find high ground so as to not have any land structures interfere with the signals). As Walshe set up each goTenna, which has a concealed relay station, he sent a transaction to see if it effectively went through. His girlfriend was waiting on the other side of each transaction, with her smartphone connected to the goTenna mesh network Walshe created. (Although an internet connection was not needed in order to receive the transaction, she was only able to confirm that the transaction was successful by checking the blockchain over the internet.) The developer was able to send a transaction from two of the three locations he used, citing that the third didn&rsquo;t go through because it was &ldquo;pushing the distance&rdquo; of the goTennas. A huge takeaway for Walshe was that, from the offline device, there was no way to know if the transaction had been received by the other party. Therefore, he would need to essentially depend upon the party on the other side, in this case his girlfriend, to accurately report back to him whether or not she had received the transaction. He noted that an analog message confirming that a successful transaction had taken place would be a huge advantage to the network. &ldquo;If this was being used in a disaster scenario ... after Hurricane Katrina, or in a hostile environment such as a prison or warzone, people may not be able to communicate to confirm the payment has actually made it onto the blockchain, as goTenna is a passive receiver system. A confirmation message would help reduce additional risk for those unable to use a solution like the Blockstream satellite for confirmation.&rdquo; So What? While the experiment can be considered a success, off-grid transactions still have a long road ahead of them before they see mainstream adoption and application. Walshe&rsquo;s own transactions were cumbersome enough, requiring that he set up specific hardware and map out a grid with multiple antennae to relay the transactions. Nonetheless, the ability to begin to experiment with possible offline solutions is a huge plus for the Bitcoin community as a whole. As Walshe notes, &ldquo;the requirement for internet access has been an objection point for bitcoin detractors since it started.&rdquo; Developments like this are important for Bitcoin, as it shows the technology being used in creative ways that are just beginning to push the boundaries of what we thought was possible. When asked how he sees the results of his experiment used in the future, Walshe said to Bitcoin Magazine, &ldquo;Hopefully other people will pick up the gauntlet and try to beat my record.&rdquo; Indeed, we have seen blockchain technology make improvements in strides by first implementing ideas in the form of a game in the past. A challenging, time-costly game at best, the infrastructure setup was the hardest part of the experiment, according to Walshe. Despite the difficulties, however, he still points out that he&rsquo;s &ldquo;going to do a few more reports using some interesting terrain.&rdquo; Walshe welcomes other Bitcoin enthusiasts to try to top him. &ldquo;There [are] some amazing things that could be done by combining goTenna and drones,&rdquo; he said. &ldquo;Let&rsquo;s see what everyone can come up with.&rdquo;

Michael is an associate at BTC Media who is passionate about the rise of Bitcoin and the downfall of the largest fiscal experiment in human history. You can follow him on Twitter @taiberg.

No Connection Required: How One Dev Sent Bitcoin While Off the Grid - bitcoinmagazine.com

Digital assets - goTenna and Samourai Wallet’s New Mobile App Works Without Internet Access

goTenna and Samourai Wallet’s New Mobile App Works Without Internet Access - Bitcoin Magazine

https://admin.bitcoinmagazine.com/wp-content/uploads/2019/06/gotennaSamourai.width-800.jpg

Digital Assets

Cryptocurrencies

Mobile

Txtenna

bitcoin transactions

gotenna mesh

gotenna mesh device

mesh device

Brooklyn-based <a data-original-title="" href="https://www.gotenna.com/">goTenna</a> has launched TxTenna, a mobile app that allows users to send bitcoin without an internet connection. Built in partnership with <a data-original-title="" href="https://samouraiwallet.com/">Samourai Wallet</a>, the mobile app will enable users to send bitcoin using a secure and private network free of censorship. 



goTenna produces consumer-grade mesh networking devices which operate by allowing peers to connect directly to one another for the purpose of routing packets, sidestepping the need to rely on an ISP or cell tower.



“TxTenna demonstrates how decentralized mesh networking can both enhance the privacy and resiliency of Bitcoin transactions, and expand Bitcoin access to people living in areas without cell or wifi connectivity,” Rich Myers, DApps engineer at goTenna, said to Bitcoin Magazine.



Internet connections are not always reliable, and in some locations, they could be unavailable due to natural disasters. This is where the TxTenna app comes into play. The app will allow users to sync their smartphones with a goTenna mesh device, then toggle the settings to send and receive bitcoin. Mesh <a data-original-title="" href="https://www.inverse.com/article/39507-mesh-networks-net-neutrality-fcc">networks</a> connect devices directly to one another, rather than going through a central point (Internet Service Provider). 



“The reality is that local carriers or ISPs can associate subscribers with their transactions or censor Bitcoin transactions altogether. TxTenna provides an answer to these problems by decentralizing the critical transport layer to enable truly decentralized bitcoin transactions,” said goTenna CEO Daniela Perdomo in a statement.



The new app, which is currently available for <a data-original-title="" href="http://txtenna.com/">Android users</a>, was built on <a data-original-title="" href="https://www.gotenna.com/pages/sdk">goTenna's open SDK</a> by Samourai Wallet developers. Explaining why Samourai Wallet was chosen for the partnership, Perdomo told Bitcoin Magazine that their MuleTools <a data-original-title="" href="https://blog.samouraiwallet.com/">initiative</a> was the difference maker.



“Late last year we began talking with the team at Samourai Wallet about including goTenna in their MuleTools initiative. The Samourai Wallet team are leaders in building advanced mobile bitcoin wallets. Inspired by Blockstream’s satellite, their open-source MuleTools initiative encourages more alternative transaction broadcast methods.”



To start transacting offline, users have to download both the Samourai Wallet mobile app and the TxTenna app, and then pair them to a goTenna Mesh device for connectivity. Once this connection is created, users can send bitcoins to anyone in the world and broadcast it on the blockchain.



“Other goTenna devices in the area relay the transaction until an internet connected goTenna node also running TxTenna receives it and forwards it to the Bitcoin network,” Myers added.



TxTenna is another step in boosting the security and diversity of internet connection across the blockchain. Last year, cryptographer Nick Szabo and blockchain engineer Elaine Ou <a href="https://scalingbitcoin.org/stanford2017/Day2/Weak-Signal-Radio-Communications-for-Bitcoin-Network-Resilience.pdf">proposed </a>alternative methods for accessing the blockchain. These methods offer much more versatility to those who wish to avoid censored systems, and it opens up use cases for bitcoin adoption in regions with less developed internet infrastructure.

In partnership with Samourai, Brooklyn-based goTenna has launched TxTenna, a mobile app that allows users to send bitcoin without an internet connection.

goTenna and Samourai Wallet&rsquo;s New Mobile App Works Without Internet Access

Brooklyn-based goTenna has launched TxTenna, a mobile app that allows users to send bitcoin without an internet connection. Built in partnership with Samourai Wallet, the mobile app will enable users to send bitcoin using a secure and private network free of censorship. goTenna produces consumer-grade mesh networking devices which operate by allowing peers to connect directly to one another for the purpose of routing packets, sidestepping the need to rely on an ISP or cell tower. &ldquo;TxTenna demonstrates how decentralized mesh networking can both enhance the privacy and resiliency of Bitcoin transactions, and expand Bitcoin access to people living in areas without cell or wifi connectivity,&rdquo; Rich Myers, DApps engineer at goTenna, said to Bitcoin Magazine. Internet connections are not always reliable, and in some locations, they could be unavailable due to natural disasters. This is where the TxTenna app comes into play. The app will allow users to sync their smartphones with a goTenna mesh device, then toggle the settings to send and receive bitcoin. Mesh networks connect devices directly to one another, rather than going through a central point (Internet Service Provider). &ldquo;The reality is that local carriers or ISPs can associate subscribers with their transactions or censor Bitcoin transactions altogether. TxTenna provides an answer to these problems by decentralizing the critical transport layer to enable truly decentralized bitcoin transactions,&rdquo; said goTenna CEO Daniela Perdomo in a statement. The new app, which is currently available for Android users, was built on goTenna&#039;s open SDK by Samourai Wallet developers. Explaining why Samourai Wallet was chosen for the partnership, Perdomo told Bitcoin Magazine that their MuleTools initiative was the difference maker. &ldquo;Late last year we began talking with the team at Samourai Wallet about including goTenna in their MuleTools initiative. The Samourai Wallet team are leaders in building advanced mobile bitcoin wallets. Inspired by Blockstream&rsquo;s satellite, their open-source MuleTools initiative encourages more alternative transaction broadcast methods.&rdquo; To start transacting offline, users have to download both the Samourai Wallet mobile app and the TxTenna app, and then pair them to a goTenna Mesh device for connectivity. Once this connection is created, users can send bitcoins to anyone in the world and broadcast it on the blockchain. &ldquo;Other goTenna devices in the area relay the transaction until an internet connected goTenna node also running TxTenna receives it and forwards it to the Bitcoin network,&rdquo; Myers added. TxTenna is another step in boosting the security and diversity of internet connection across the blockchain. Last year, cryptographer Nick Szabo and blockchain engineer Elaine Ou proposed alternative methods for accessing the blockchain. These methods offer much more versatility to those who wish to avoid censored systems, and it opens up use cases for bitcoin adoption in regions with less developed internet infrastructure.

goTenna and Samourai Wallet’s New Mobile App Works Without Internet Access

goTenna and Samourai Wallet’s New Mobile App Works Without Internet Access - bitcoinmagazine.com

Adoption & community - Samourai and goTenna Enable Bitcoin Transactions Without Internet Access

Samourai and goTenna Enable Bitcoin Transactions Without Internet Access - Bitcoin Magazine

https://admin.bitcoinmagazine.com/wp-content/uploads/2019/06/extenna.width-800.jpg

Blockchain

Internet

Mesh network

Transactions

allow

censorship resistance

concept

disasters

mesh

mesh networking

<a href="https://samouraiwallet.com/">Samourai Wallet</a> is collaborating with <a href="https://www.gotenna.com/">goTenna</a>, a Brooklyn-based company specializing in off-grid communications, to produce txTenna, an Android app that combines mesh networking with Bitcoin transactions. The app will allow users to pair their phones with goTenna’s portable antennas in order to broadcast transactions. 



goTenna produces consumer-grade hardware to facilitate mesh networking — a concept that echoes much of the decentralization ethos that we see across the cryptocurrency domain — which operates by allowing peers to connect directly to one another for the purpose of routing packets, sidestepping the need to rely on an ISP or cell tower.



“What will happen when these massive centralized networks fail due to natural disasters, as they did after Hurricane Sandy in 2012, or due to some kind of outside cybersecurity attack? What will happen when providers decide to crank up prices just because they can?” said Rich Myers, goTenna’s Decentralized Applications Engineer. 



“Mesh networks are the only legitimate alternative to these traditional centralized communication networks. They are completely decentralized and democratized, leaving the power of communication in the hands of the people. Beyond that, they are much more resilient to unforeseen disasters — the only thing these networks need to function is a mesh networking device paired with a smartphone.”



For its part, Samourai Wallet has been focusing on censorship resistance and privacy-oriented tools since it began in 2015. With features such as direct interaction with trusted nodes, added hops to circumvent chain analysis, and SMS commands for remotely wiping wallets, it has seen widespread adoption by users wishing to incorporate an additional level of privacy into their Bitcoin transactions.



Samourai has been curating <a data-original-title="" href="http://mule.tools">Mule.tools</a>, an R&D initiative to further reinforce the censorship-resistant properties of the Bitcoin blockchain and also published the code for <a data-original-title="" href="https://github.com/MuleTools/PonyDirect">Pony Direct</a>, a proof-of-concept app for broadcasting transactions over SMS in January.



“We believe one of the most fundamental value propositions that bitcoin provides is censorship resistance,” SW, the CEO of Samourai, told Bitcoin Magazine. “The freedom to transact freely and without permission is not a freedom to take lightly, or give up without a fight. We saw the open internet transform into a walled garden, captured by regulatory and corporate interest working together — and largely aided by red-herrings like ‘net-neutrality.’



“The tools we are building arm the little guy — the individual — with the tools they need to level the playing field against the inevitable overstepping of bounds by hostile actors, oppressive regimes and overzealous governments,” said SW. “We're making some material changes to Samourai Wallet to allow for a greater high latency and offline experience. In conjunction with the release of txTenna, Samourai Wallet users will be able to theoretically keep their phone offline at all times and still be able to send and receive payments with minimal hassle.”



The concept explored by txTenna follows in the path of alternate methods to access the blockchain, previously seen with both the <a href="https://github.com/blockstream/satellite">Blockstream Satellite</a> and in the <a href="https://youtu.be/QkYXPJMqBNk?t=4968">works</a> of Nick Szabo and Elaine Ou. Not only does it provide more versatility to those wishing to avoid using censored systems, but it opens up a slew of use cases for Bitcoin in regions with less-developed infrastructures and those affected by natural disasters.

Matt B. is a recent law graduate and freelance writer specializing in cryptocurrency and blockchain technology. Twitter: @MattoshiN

Matthew B.

Samourai Wallet is collaborating with goTenna, a Brooklyn-based company specializing in off-grid communications, to produce txTenna, an Android app that combines mesh networking with Bitcoin transactions. The app will allow users to pair their...

Samourai and goTenna Enable Bitcoin Transactions Without Internet Access

Samourai Wallet is collaborating with goTenna, a Brooklyn-based company specializing in off-grid communications, to produce txTenna, an Android app that combines mesh networking with Bitcoin transactions. The app will allow users to pair their phones with goTenna&rsquo;s portable antennas in order to broadcast transactions. goTenna produces consumer-grade hardware to facilitate mesh networking &mdash; a concept that echoes much of the decentralization ethos that we see across the cryptocurrency domain &mdash; which operates by allowing peers to connect directly to one another for the purpose of routing packets, sidestepping the need to rely on an ISP or cell tower. &ldquo;What will happen when these massive centralized networks fail due to natural disasters, as they did after Hurricane Sandy in 2012, or due to some kind of outside cybersecurity attack? What will happen when providers decide to crank up prices just because they can?&rdquo; said Rich Myers, goTenna&rsquo;s Decentralized Applications Engineer. &ldquo;Mesh networks are the only legitimate alternative to these traditional centralized communication networks. They are completely decentralized and democratized, leaving the power of communication in the hands of the people. Beyond that, they are much more resilient to unforeseen disasters &mdash; the only thing these networks need to function is a mesh networking device paired with a smartphone.&rdquo; For its part, Samourai Wallet has been focusing on censorship resistance and privacy-oriented tools since it began in 2015. With features such as direct interaction with trusted nodes, added hops to circumvent chain analysis, and SMS commands for remotely wiping wallets, it has seen widespread adoption by users wishing to incorporate an additional level of privacy into their Bitcoin transactions. Samourai has been curating Mule.tools, an R&amp;D initiative to further reinforce the censorship-resistant properties of the Bitcoin blockchain and also published the code for Pony Direct, a proof-of-concept app for broadcasting transactions over SMS in January. &ldquo;We believe one of the most fundamental value propositions that bitcoin provides is censorship resistance,&rdquo; SW, the CEO of Samourai, told Bitcoin Magazine. &ldquo;The freedom to transact freely and without permission is not a freedom to take lightly, or give up without a fight. We saw the open internet transform into a walled garden, captured by regulatory and corporate interest working together &mdash; and largely aided by red-herrings like &lsquo;net-neutrality.&rsquo; &ldquo;The tools we are building arm the little guy &mdash; the individual &mdash; with the tools they need to level the playing field against the inevitable overstepping of bounds by hostile actors, oppressive regimes and overzealous governments,&rdquo; said SW. &ldquo;We&#039;re making some material changes to Samourai Wallet to allow for a greater high latency and offline experience. In conjunction with the release of txTenna, Samourai Wallet users will be able to theoretically keep their phone offline at all times and still be able to send and receive payments with minimal hassle.&rdquo; The concept explored by txTenna follows in the path of alternate methods to access the blockchain, previously seen with both the Blockstream Satellite and in the works of Nick Szabo and Elaine Ou. Not only does it provide more versatility to those wishing to avoid using censored systems, but it opens up a slew of use cases for Bitcoin in regions with less-developed infrastructures and those affected by natural disasters.

Samourai Wallet is collaborating with goTenna, a Brooklyn-based company specializing in off-grid communications, to produce txTenna, an Android app that combines mesh networking with Bitcoin transactions. The app will allow users to pair their phones with goTenna’s portable antennas in order to broadcast transactions. goTenna produces consumer-grade hardware to facilitate mesh networking — a concept […]

Samourai and goTenna Enable Bitcoin Transactions Without Internet Access - bitcoinmagazine.com

Privacy & security - HiddenWallet and Samourai Wallet Join Forces to Make Bitcoin Private With ZeroLink

HiddenWallet and Samourai Wallet Join Forces to Make Bitcoin Private With ZeroLink - Bitcoin Magazine

https://admin.bitcoinmagazine.com/wp-content/uploads/2019/06/ZEROLINK_hKM2oHV.width-800.jpg

Hiddenwallet

Tumblebit

bitcoin addresses

bitcoins

bitcoins move

bitcoins moved

chaumian coinjoin

coinjoin

coinjoin transaction

outputs

post-mix wallet

Ádám “nopara73” Ficsór, <a href="https://bitcoinmagazine.com/articles/privacy-project-tumblebit-inches-closer-release-tor-integration-and-new-wallet/">HiddenWallet</a> developer and<a href="https://bitcoinmagazine.com/articles/better-bitcoin-privacy-scalability-developers-are-making-tumblebit-reality/"> TumbleBit contributor</a>, and “TDevD,” the pseudonymous<a href="https://github.com/Samourai-Wallet" rel="noopener external noreferrer" target="_blank"> Samourai wallet</a> developer, are joining forces on a new privacy project: ZeroLink. ZeroLink is set to realize a trustless mixing scheme first<a href="https://bitcointalk.org/index.php?topic=279249.0" rel="noopener external noreferrer" target="_blank"> proposed</a> by<a href="https://bitcoincore.org/" rel="noopener external noreferrer" target="_blank"> Bitcoin Core</a> contributor Gregory Maxwell years ago — but one that hasn’t been realized thus far. 



According Ficsór, the ZeroLink framework, which utilizes a scheme known as “Chaumian CoinJoin,” is actually more straightforward than many of the alternatives that have been proposed.



“Back in 2013, there was this sort of obsession with decentralization. ‘Everything that can be decentralized will be decentralized’ was the slogan,” the developer recalls. “By now we realize that decentralization is actually not always that useful. As long as a mixer cannot steal funds or link transactions, that’s enough.”



<h4>CoinJoin</h4>



Each Bitcoin transaction essentially sends bitcoins from one or several Bitcoin addresses (really: “inputs”) to one or several Bitcoin addresses (really: “outputs”). That’s how bitcoins “move” over the blockchain.



The problem, from a privacy perspective, is that the blockchain is completely public, which means that anyone can see which addresses are paying which addresses. If these addresses can be linked to real-world identities, it can reveal a lot about who transacted with whom, and perhaps for what.



<a href="https://bitcoinmagazine.com/articles/coinjoin-combining-bitcoin-transactions-to-obfuscate-trails-and-increase-privacy-1465235087/">CoinJoin</a>, the well-known coin-mixing scheme first proposed by Maxwell in 2013, is a potential solution to this problem. A CoinJoin transaction is basically a combination of several transactions merged into one big transaction. In other words, it includes inputs from several different users, and the bitcoins move to outputs controlled by several different users. As such, it’s not clear which bitcoins moved where. All users effectively paid all users.



While that’s great, the next problem is that whomever or whatever combines the different transactions into one CoinJoin transaction can be a central point of failure from a privacy perspective. That person (or that server, or whatever it is) still knows which bitcoins moved where. So if that individual is either corrupt or corruptible, the problem isn’t really solved.



“For CoinJoin to live up to its promise, even the entity that creates the transaction must not learn which addresses are paying which addresses,” Ficsór noted.



<h4>ZeroLink</h4>



ZeroLink provides a privacy framework for wallets that can be used for different mixing schemes. And it defines its own mixing technique as well: an implementation of CoinJoin referred to as “Chaumian CoinJoin.” 



With Chaumian CoinJoin, users both send and receive equal amounts of bitcoin from a CoinJoin transaction, so everyone receives each other's coins. This obfuscates the trails for all of these coins.



In practice, ZeroLink users will require two types of wallets: a pre-mix wallet and a post-mix wallet. As the names suggest, the first type holds coins that are to be mixed, while the latter is where the mixed coins end up.



Users then connect their pre-mix wallets to the ZeroLink tumbler and provide an input (“from” address) and an output (“to” address), which they both control. But importantly, the outputs are disguised (“blinded”) using a mathematical trick. So while the tumbler knows where all bitcoins are sent from, it does not yet know where bitcoins are sent to.



At the heart of the trick, the tumbler then cryptographically signs all blinded outputs, using a type of cryptographic signature introduced by David Chaum: a “<a href="https://en.wikipedia.org/wiki/Blind_signature" rel="noopener external noreferrer" target="_blank">blind signature</a>.” This allows data to be cryptographically signed even if it is disguised. And importantly, these signatures can be checked against the original, unblinded data as well to see if the blinded data and the unblinded data match.



Next, all users connect to the tumbler again, but this time through some type of anonymity network, like Tor. They will then provide the tumbler with the unblinded versions of the outputs. Using the cryptographic signatures it just created, the tumbler can check that all revealed outputs match all blinded outputs. If they do match, the tumbler knows that all the outputs it received are legitimate, and thus were provided by the same users that also provided the inputs to send funds.



The tumbler then adds the revealed outputs to the CoinJoin transaction. And it sends this transaction back to all users, for these users to sign with their Bitcoin private keys. Doing so validates the transaction. (The users should of course double check that the amounts and their outputs check out, to be sure they receive as much as they send.)



Finally, the tumbler broadcasts the CoinJoin transaction to be included in a Bitcoin block. As a result, all users end up with different bitcoins than they started with: all bitcoins were mixed, and the blockchain trails broken.



While all this is actually relatively straightforward compared to some alternative schemes, and to a large extent already suggested by Maxwell back in 2013, the process has never been realized. This is probably because it was long thought to be too vulnerable to attacks, Ficsór thinks.



“When Maxwell first published the proposal, Bitcoin transaction fees were practically non-existent. Because of this, it would be relatively easy and cheap to launch denial of service attacks against a CoinJoin mixing system. An attacker can just keep providing valid inputs, but refuse to sign when he should. That invalidates the whole transaction, and wastes everyone’s time.”



Interestingly, this attack vector is now to some extent resolved simply because it would be too expensive to keep it going. In order to maintain the attack in a way that it’s not easily countered, an attacker must provide new inputs for each round, meaning he must be able to keep moving bitcoins to new addresses to do so. “Assuming $1 transaction fees, that could cost up to $1,000 a day,” Ficsór pointed out. “In this particular context, high fees are a blessing in disguise.”



<h4>Development</h4>



Ficsór is currently about to help wrap up the development of another highly anticipated privacy tool,<a href="https://bitcoinmagazine.com/articles/with-tumblebit-bitcoin-mixing-may-have-found-its-winning-answer-1477423607/"> TumbleBit</a>, for Stratis’s<a href="https://bitcoinmagazine.com/articles/bitcoin-privacy-all-breeze-wallet-about-bring-tumblebit-life/"> Breeze Wallet</a>. This is expected to take another three months.



After that, he plans to focus on realizing ZeroLink, while TDevD may even start working on the framework sooner. Concretely, three new codebases need to be developed: the pre-mix wallet, the tumbler and the post-mix wallet.



“The tumbler needs to be developed from scratch. But it should be relatively easy to add the pre-mix wallets to any existing open source wallet. The same is true for the post-mix wallet implementations, though for privacy reasons not all wallets are a good fit,” Ficsór said.



His own HiddenWallet as well as Samourai Wallet are “fully committed” to implementing and deploying ZeroLink into production, Ficsór said, while Breeze Wallet may be interested as well. 



Optimistically, an initial implementation of ZeroLink could be live before the end of this year.



For more information on ZeroLink, see Ficsór's<a href="https://medium.com/@nopara73/introducing-zerolink-the-bitcoin-fungibility-framework-dc5338086198" rel="noopener external noreferrer" target="_blank"> blog post</a> on the project (which also includes a<a href="https://www.smartbit.com.au/address/186n7me3QKajQZJnUsVsezVhVrSwyFCCZ" rel="noopener external noreferrer" target="_blank"> donation address</a>) or<a href="https://github.com/nopara73/ZeroLink/" rel="noopener external noreferrer" target="_blank"> ZeroLink’s specification</a>.

&Aacute;d&aacute;m &ldquo;nopara73&rdquo; Fics&oacute;r, HiddenWallet developer and TumbleBit contributor, and &ldquo;TDevD,&rdquo; the pseudonymous Samourai wallet developer, are joining forces on a new privacy project: ZeroLink. ZeroLink is set to realize a trustless mixing scheme first...

HiddenWallet and Samourai Wallet Join Forces to Make Bitcoin Private With ZeroLink

&Aacute;d&aacute;m &ldquo;nopara73&rdquo; Fics&oacute;r, HiddenWallet developer and TumbleBit contributor, and &ldquo;TDevD,&rdquo; the pseudonymous Samourai wallet developer, are joining forces on a new privacy project: ZeroLink. ZeroLink is set to realize a trustless mixing scheme first proposed by Bitcoin Core contributor Gregory Maxwell years ago &mdash; but one that hasn&rsquo;t been realized thus far. According Fics&oacute;r, the ZeroLink framework, which utilizes a scheme known as &ldquo;Chaumian CoinJoin,&rdquo; is actually more straightforward than many of the alternatives that have been proposed. &ldquo;Back in 2013, there was this sort of obsession with decentralization. &lsquo;Everything that can be decentralized will be decentralized&rsquo; was the slogan,&rdquo; the developer recalls. &ldquo;By now we realize that decentralization is actually not always that useful. As long as a mixer cannot steal funds or link transactions, that&rsquo;s enough.&rdquo; CoinJoin. Each Bitcoin transaction essentially sends bitcoins from one or several Bitcoin addresses (really: &ldquo;inputs&rdquo;) to one or several Bitcoin addresses (really: &ldquo;outputs&rdquo;). That&rsquo;s how bitcoins &ldquo;move&rdquo; over the blockchain. The problem, from a privacy perspective, is that the blockchain is completely public, which means that anyone can see which addresses are paying which addresses. If these addresses can be linked to real-world identities, it can reveal a lot about who transacted with whom, and perhaps for what. CoinJoin, the well-known coin-mixing scheme first proposed by Maxwell in 2013, is a potential solution to this problem. A CoinJoin transaction is basically a combination of several transactions merged into one big transaction. In other words, it includes inputs from several different users, and the bitcoins move to outputs controlled by several different users. As such, it&rsquo;s not clear which bitcoins moved where. All users effectively paid all users. While that&rsquo;s great, the next problem is that whomever or whatever combines the different transactions into one CoinJoin transaction can be a central point of failure from a privacy perspective. That person (or that server, or whatever it is) still knows which bitcoins moved where. So if that individual is either corrupt or corruptible, the problem isn&rsquo;t really solved. &ldquo;For CoinJoin to live up to its promise, even the entity that creates the transaction must not learn which addresses are paying which addresses,&rdquo; Fics&oacute;r noted. ZeroLink. ZeroLink provides a privacy framework for wallets that can be used for different mixing schemes. And it defines its own mixing technique as well: an implementation of CoinJoin referred to as &ldquo;Chaumian CoinJoin.&rdquo; With Chaumian CoinJoin, users both send and receive equal amounts of bitcoin from a CoinJoin transaction, so everyone receives each other&#039;s coins. This obfuscates the trails for all of these coins. In practice, ZeroLink users will require two types of wallets: a pre-mix wallet and a post-mix wallet. As the names suggest, the first type holds coins that are to be mixed, while the latter is where the mixed coins end up. Users then connect their pre-mix wallets to the ZeroLink tumbler and provide an input (&ldquo;from&rdquo; address) and an output (&ldquo;to&rdquo; address), which they both control. But importantly, the outputs are disguised (&ldquo;blinded&rdquo;) using a mathematical trick. So while the tumbler knows where all bitcoins are sent from, it does not yet know where bitcoins are sent to. At the heart of the trick, the tumbler then cryptographically signs all blinded outputs, using a type of cryptographic signature introduced by David Chaum: a &ldquo;blind signature.&rdquo; This allows data to be cryptographically signed even if it is disguised. And importantly, these signatures can be checked against the original, unblinded data as well to see if the blinded data and the unblinded data match. Next, all users connect to the tumbler again, but this time through some type of anonymity network, like Tor. They will then provide the tumbler with the unblinded versions of the outputs. Using the cryptographic signatures it just created, the tumbler can check that all revealed outputs match all blinded outputs. If they do match, the tumbler knows that all the outputs it received are legitimate, and thus were provided by the same users that also provided the inputs to send funds. The tumbler then adds the revealed outputs to the CoinJoin transaction. And it sends this transaction back to all users, for these users to sign with their Bitcoin private keys. Doing so validates the transaction. (The users should of course double check that the amounts and their outputs check out, to be sure they receive as much as they send.) Finally, the tumbler broadcasts the CoinJoin transaction to be included in a Bitcoin block. As a result, all users end up with different bitcoins than they started with: all bitcoins were mixed, and the blockchain trails broken. While all this is actually relatively straightforward compared to some alternative schemes, and to a large extent already suggested by Maxwell back in 2013, the process has never been realized. This is probably because it was long thought to be too vulnerable to attacks, Fics&oacute;r thinks. &ldquo;When Maxwell first published the proposal, Bitcoin transaction fees were practically non-existent. Because of this, it would be relatively easy and cheap to launch denial of service attacks against a CoinJoin mixing system. An attacker can just keep providing valid inputs, but refuse to sign when he should. That invalidates the whole transaction, and wastes everyone&rsquo;s time.&rdquo; Interestingly, this attack vector is now to some extent resolved simply because it would be too expensive to keep it going. In order to maintain the attack in a way that it&rsquo;s not easily countered, an attacker must provide new inputs for each round, meaning he must be able to keep moving bitcoins to new addresses to do so. &ldquo;Assuming $1 transaction fees, that could cost up to $1,000 a day,&rdquo; Fics&oacute;r pointed out. &ldquo;In this particular context, high fees are a blessing in disguise.&rdquo; Development. Fics&oacute;r is currently about to help wrap up the development of another highly anticipated privacy tool, TumbleBit, for Stratis&rsquo;s Breeze Wallet. This is expected to take another three months. After that, he plans to focus on realizing ZeroLink, while TDevD may even start working on the framework sooner. Concretely, three new codebases need to be developed: the pre-mix wallet, the tumbler and the post-mix wallet. &ldquo;The tumbler needs to be developed from scratch. But it should be relatively easy to add the pre-mix wallets to any existing open source wallet. The same is true for the post-mix wallet implementations, though for privacy reasons not all wallets are a good fit,&rdquo; Fics&oacute;r said. His own HiddenWallet as well as Samourai Wallet are &ldquo;fully committed&rdquo; to implementing and deploying ZeroLink into production, Fics&oacute;r said, while Breeze Wallet may be interested as well. Optimistically, an initial implementation of ZeroLink could be live before the end of this year. For more information on ZeroLink, see Fics&oacute;r&#039;s blog post on the project (which also includes a donation address) or ZeroLink&rsquo;s specification.

Ádám “nopara73” Ficsór, HiddenWallet developer and TumbleBit contributor, and “TDevD,” the pseudonymous Samourai wallet developer, are joining forces on a new privacy project: ZeroLink. ZeroLink is set to realize a trustless mixing scheme first proposed by Bitcoin Core contributor Gregory Maxwell years ago — but one that hasn’t been realized thus far. According Ficsór, the […]

HiddenWallet and Samourai Wallet Join Forces to Make Bitcoin Private With ZeroLink - bitcoinmagazine.com

Startups - This New Tool Can Help Bitcoin Users Deal With Stuck Transactions

Bitcoin Afterburner allows users of many different bitcoin wallets to boost transactions that have become stuck due to low fees.

This New Tool Can Help Bitcoin Users Deal With Stuck Transactions - Bitcoin Magazine

https://admin.bitcoinmagazine.com/wp-content/uploads/2019/06/samourai-stuck.width-800.jpg

Tags

Samourai