Privacy.Bitcoin.com is coming soon!

[rogerver]

It's time to think about how to design an easy to use Bitcoin privacy tool at privacy.bitcoin.com

Ideally I would like it to be as easy to use as Shapeshift.io, but break custody of the coins that come in and out.

1. Bitcoins come in
2. Different Bitcoins go out.
Result: Private Bitcoin transaction thanks to Bitcoin.com


Currently we are brainstorming ways to do this.
Ideally it would be something non custodial so we don't need to block users in New York and North Korea.

Some possible tools to use for this are:
CoinJoin
JoinMarket
Shapeshift.io
Blockchain.info's receive payment API
Other cools things that I'm not aware of yet.

The goal is to provide a tool that easily and safely allows anyone in the world to transact with additional financial privacy.

I would love to hear suggestions the community has on the best way to build this.

[hakuna_potato]

Thanks for sparking this. privacy.bitcoin.com could be an intuitive front-end for a mixer.

I don't imagine you're interested in holding anyone's btc. CoinParty has a pretty good start on a secure multi-party mixer described in their white paper.

The actual gears of such a system would need to be provably fair, something Satoshi Dice does pretty well.

[hakuna_potato]

Wouldn't a quick-and-dirty method be to execute two ShapeShift transactions?

Code: Select all

BTC -> LTC LTC -> BTC

nvm, answered my own question. From ShapeShift's Help Center:

ShapeShift holds relatively small hot wallets in order to process instant transactions so there is a pretty decent chance you will end up getting the exact same coins back, it's just random.

It's important to note ShapeShift is not designed nor intended to be used as a mixing or tumbling service. We do not endorse the use of ShapeShift in such a manner and likely it won't achieve your goals if you try to use it in such a way as there is a good chance you will get the same coins back you started with. Any clearly suspicious activity may be reported to relevant authorities.

tl;dr It could be used, but it shouldn't.

[rogerver]

Earlier today we were looking into this exact same thing, and came to your exact same conclusion.

[hellobitcoinworld]

This is a brilliant idea and one of the biggest missing features from Bitcoin. Once the issue of privacy is resolved, this will enhance Bitcoin's utility and value even further. I hope you carry this through to completion, Roger.

I believe one of the most important factors that should be maintained is the lowest fee possible for such a service, to make it easy and desirable to use. This is why it's undesirable to send coins to an exchange, convert them to another coin, and then convert them back to bitcoin. Otherwise that solution would already be good.

In the past there was the idea of "ZeroCoin", but I'm not sure what happened to that, or if it's still in the works. If you read that linked page you will see it's exactly what you're talking about here.

Another past idea that never came to full fruition was Dark Wallet

And lastly, CoinJoin as you mention.

[LiteCoinGuy]

wow, that is a valuable addon. in the future it could be something like Zerocash (sidechain in BTC).

@hellobitcoinworld

still in the works. the name is Zerocash now. it will probably be a sidechain in bitcoin at some point.

[rogerver]

There are several upcoming projects that I am aware of that will improve the privacy aspect.

Another is Moneta

It would be nice to have something that adds a little bit of privacy now, while we wait for the iron clad alternatives to be created.

[hakuna_potato]

One idea:

Users send btc to escrow accounts hosted by bitcoin.com. This amount can be withdrawn before the mixing is executed. The user waits for an appropriate amount to be deposited by other users with which it can be mixed. The user can potentially define how many times removed or split they would like their resulting coins to be, but would clearly have to wait longer for enough btc to become available in escrow.

Once enough btc is held in escrow, the service could slice-and-dice with newly generated keys and return the same amount to the user.

Thoughts? Errors? Improvements?

[rogerver]

Another suggestion:

https://twitter.com/maraoz/status/652521041902702592

[JuanSGalt]

What ever happened to stealth addresses? It seems all we need is a mobile wallet that implements it and we'll have a great tool make public keys private.

Long story short, from my non technical understanding, it is some cryptographic machination of the public key, such that when you send btc to the stealth address, it is redirected to a public key of your choosing, but one that you have not nessesarily published online, or made known to others.

This should avoid social media or other kinds of data mining that could be used to associate identities with public keys.

I wager it is not easy to set up however since no wallet has implemented it to my knowledge. Except the now dormant dark wallet. They had a good thing going, maybe we should revive that project, it is open source after all, it just needs new developers. And it won the fist place as far as anon bitcoin wallets with its federated coinjoin system.

That might be the way to go actually. Or one worth exploring.

Since it is federated, you'll distribute the risk of attack. If bitcoin.com is taking the heat for doing coinmixing, I bet the powers that be might end up letting lose their AML lawyers at you. If it is going to be centralized, it really should be an anonymously run website.

http://cointelegraph.com/news/115215/da ... rs-go-dark

[SamouraiDev]

We have made very big progress in implementing BIP47 payment codes (stealth addresses for SPV/mobile) and you will all be seeing them in an upcoming version of Samourai Wallet. All of the building blocks are in place and now we just have to fit them together in an easy-to-use UI and work them into our wallet app. Join us at http://samouraiwallet.com . Read up on BIP47 payment codes at https://github.com/bitcoin/bips/blob/ma ... .mediawiki

Excuse this being off-topic. I was responding to the preceding post. Many thanks to Roger for putting together this great forum.

[JuanSGalt]

We have made very big progress in implementing BIP47 payment codes (stealth addresses for SPV/mobile) and you will all be seeing them in an upcoming version of Samourai Wallet. All of the building blocks are in place and now we just have to fit them together in an easy-to-use UI and work them into our wallet app. Join us at http://samouraiwallet.com . Read up on BIP47 payment codes at https://github.com/bitcoin/bips/blob/ma ... .mediawiki

Excuse this being off-topic. I was responding to the preceding post. Many thanks to Roger for putting together this great forum.

Cool! I'll check it out. You should try to be on the next Open Bitcoin Privacy Project report if you have not participated yet.

[SamouraiDev]

OBPP is doing excellent work in the area of privacy when transacting in Bitcoin. We are very happy to work closely to their guidelines and have already implemented their BIP pertaining to deterministic sorting of tx inputs & outputs. ...and we are anxiously awaiting the results of the latest round of wallet evaluations

[gold]

Thoughts? Errors? Improvements?

Implemented here:
http://deepmix.ws/faq.html
Haven't used it, though.

The other day I visited this Github project that allows people to run a mixing service and name their own fees, but I can't find it now.
Some people were running mixing nodes for free.

[jamie.redman1]

I am a fan of the cryptonotes. I think encryption wise they provide superior privacy than coinjoin or shuffling scenarios. I'm also a fan of the samourai wallet, I like certain aspects of Dash, and I do have some Zero.

This is pretty cool. ~> https://www.comsys.rwth-aachen.de/filea ... nparty.pdf

[krisives]

I'm interested in helping with the implementation if anyone wants my help.

Glad to see you again Roger!

Hi Jamie!

[djleo]

Monero uses ring signatures which obfuscates the blockchain very well. Alt coin exchanges are certainly the weak points - there really needs to be more competition in this space.

[DiggnDeeper]

This looks promising...

http://www.supernet.org/blog/2015/09/18 ... fee-agent/

[rogerver]

I'm interested in helping with the implementation if anyone wants my help.

Can you tell us more about what you would have in mind?

[avgeca]

bitcoin and real privacy are really hard to bring together at the moment. sad but true.
and a mixer can only do so little compared to a real untracebale but still fungible crypto currency like monero.

-> https://www.reddit.com/r/Monero/comment ... nce_tools/

as soon as the mainstream blacklisting/tainting of bitcoin addresses starts, people will realize that. and a bitcoin mixer is most likely not going to help. what are you going to do if your "bad coins" are mixed with even worse ones? which is going to happen increasingly over time.

financial privacy has to be implemented deep into the core of a crypto currency to work, add-ons are simply not enough. opaque transactions and blockchains should always be the default with the possibility to opt-out where necessary.

bitcoin is awsome, but not for privacy.

[LiteCoinGuy]

you dont need monero or another altcoin for that. you can do pretty much with bitcoin to gain better privacy. and someday there will be sidechains too.

but i agree that there will be altcoins that target that niche-market for a long time.

[avgeca]

you dont need monero or another altcoin for that. you can do pretty much with bitcoin to gain better privacy. and someday there will be sidechains too.

but i agree that there will be altcoins that target that niche-market for a long time.

nope, that's wrong.

currently you can't have the same anonymity with bitcoin that you have with ring signatures and monero. mixing won't lead you far or can even be counterproductive and other stuff like sidechains and/or privacy enhacing code changes to bitcoin are not even in sight. most bitcoin related solutions are either inferior in their current state or (like zerocash) are vaporware at the moment.

[LiteCoinGuy]

vaporware today but not "tomorrow". and everything starts with a concept in the first place. zerocash is in development since 2 years.
maybe some altcoins are better for privacy today (i agree with you) but this must not be the case tomorrow. and in the end we need a solution for bitcoin. no altcoin will win against bitcoin (probably not even Litecoin )

---------------

Forensics and Bitcoin

This article does not attempt to provide a beginners guide to Bitcoin, nor an in-depth thesis on Bitcoin forensics. Rather, it will be an overview of the potential opportunities available to digital forensics and traditional investigators to obtain evidence in relation to attributing transactions or holdings to a specific person and (legally) seizing those funds.

http://articles.forensicfocus.com/2015/ ... s-bitcoin/

[eragmus]

I've reviewed all the posts in this thread and, while disappointingly there has been some altcoin spam (despite the clear "Bitcoin Privacy" topic), it's also been clear we don't have many options in Bitcoin that truly protect privacy in a quality manner (trustless, low cost, open source to make transparent how the service works, validated by experts). It's easy for people to claim a product or service helps privacy, but privacy is actually very hard to get right. I think this point is essential to understand and remember.

The ready-right-now options I saw were: Jumblr and Shiftd.xyz -- Jumblr is very new and experimental and still being tested and refined, while Shiftd.xyz is as far as I can see a completely opaque service that does not reveal how it works, nor what information is recorded when converting between BTC & LTC. It's also a web service, with no cryptographic guarantee that funds will not be stolen. Lastly, it has an atrocious 5% fee, which is super high. Thus, it's basically "privacy theatre".

We do have one good option though, and it's ready now. It is the service Roger mentioned in his first post: "JoinMarket", but which I was sad to see did not get any further attention or elaboration.

Although there is no GUI yet (still in development), there is a command line interface. It's not that difficult to use and, most importantly, it actually works and is robust: trustless as it uses smart contract tech to keep private keys with user / less than 0.002% fee on average / open source on GitHub / based on tested CoinJoin technology / peer-reviewed by Greg Maxwell (cryptographer and Bitcoin's privacy expert & inventor of 'CoinJoin' & co-inventor of 'Confidential Transactions' with Dr. Adam Back). -- As a point of comparison here, the 0.002% fee I cited is 2,500x cheaper than the 5% fee of the other shiftd.xyz service.

JoinMarket is also a very active project. Here is the order book showing all the people who have locked their bitcoins, providing liquidity, to allow people to CoinJoin with them:
http://www.joinmarket.io

And here's the GitHub:
https://github.com/chris-belcher/joinmarket

Lastly, here's a great infographic that nicely summarizes JoinMarket's concept:

[krisives]

@rogverver, I was speaking of a JoinMarket implementation, sorry.

@eragmus Great points and well put.

My only gripe is that I would prefer a system where the coins have never touched each other. For example, in the graphic you see addresses A, B, and C making a join and the coins are delivered to addresses D, E, and F. I don't like that there is a link between the addresses in the blockchain. I still think JoinMarket is a good starting point though, and maybe I'm just wrong about how the addresses look on a graph or how large actual joins will be. It's a blessing and a curse, because the smart contract (P2SH) part is the part that exposes the most information about the addresses. In theory it would be nice if the money can move around without history on the blockchain, but then we're not a smart contract anymore =(

TL;DR - JoinMarket is good because it's a P2SH solution but leaves a trail in the blockchain, whereas a solution that doesn't won't be decentralized.

[bitcoin]

Roger, I appreciate the importance of privacy, but providing a Bitcoin mixer on bitcoin.com would aid people involved in illegal activities, and may seriously impact the reputation of your website. I'm curious to know if this is something you have given any thought to.

I'm also confused about what the purpose of this thread is. Are you asking how to build a Bitcoin mixer? There are many resources and whitepapers on this subject that are readily available. Or, are you looking for someone to hire to build it for you?

[krisives]

I appreciate the importance of privacy, but providing a Bitcoin mixer on bitcoin.com would aid people involved in illegal activities

I'm sorry but "illegal activities" doesn't matter to most considering it can be crafted and manipulated to mean anything. I'm pretty sure Roger knows that first hand from his eBay experience.

Either way if we are going to entertain this discussion of "people should have nothing to hide" put me down as a "Bitcoin is speech", something everyone should have the freedom to execute regardless of the geographical location. If you think I'm posturing for the sake of debate Google "Kristopher Ives Snowden".

[belcher]

@rogverver, I was speaking of a JoinMarket implementation, sorry.

@eragmus Great points and well put.

My only gripe is that I would prefer a system where the coins have never touched each other. For example, in the graphic you see addresses A, B, and C making a join and the coins are delivered to addresses D, E, and F. I don't like that there is a link between the addresses in the blockchain. I still think JoinMarket is a good starting point though, and maybe I'm just wrong about how the addresses look on a graph or how large actual joins will be. It's a blessing and a curse, because the smart contract (P2SH) part is the part that exposes the most information about the addresses. In theory it would be nice if the money can move around without history on the blockchain, but then we're not a smart contract anymore =(

TL;DR - JoinMarket is good because it's a P2SH solution but leaves a trail in the blockchain, whereas a solution that doesn't won't be decentralized.

I don't see why coins "touching each other" is a bad thing. As bitcoin transactions are many-to-many mappings, eventually every coin touches every other coin anyway. If our aim is defending privacy against an attacker spy who wants to find what you do with your money, then JoinMarket is effective at doing that. It ends with so many addresses touching your coins that spies don't know which addresses are "really" yours.

By the way, JoinMarket does not use P2SH. Almost all transactions use pay-to-pubkey-hash addresses. For more details on how the JoinMarket smart contract works, read this https://www.reddit.com/r/joinmarket/com ... contracts/ You can have a smart contract without using P2SH.

[bitcoin]

I appreciate the importance of privacy, but providing a Bitcoin mixer on bitcoin.com would aid people involved in illegal activities

I'm sorry but "illegal activities" doesn't matter to most considering it can be crafted and manipulated to mean anything. I'm pretty sure Roger knows that first hand from his eBay experience.

Either way if we are going to entertain this discussion of "people should have nothing to hide" put me down as a "Bitcoin is speech", something everyone should have the freedom to execute regardless of the geographical location. If you think I'm posturing for the sake of debate Google "Kristopher Ives Snowden".

I'm with you on the whole "Bitcoin is speech" mentality but that's not what I'm after. There are risks associated with building a mixer and I was curious to hear Roger's opinion on the matter. I'm all for privacy, but mixers will inevitably be used for money laundering. I'm not sure that bitcoin.com is an appropriate place to host it if he wants the world to see it as a trustworthy, legitimate website.

[BTCLuke]

Adding a mixer itself to the site is of course a way to invite a black helicopter full of armed 'Muricans over to your server room, KimDotCom style. There's a reason that the oldest ones today are all on the dark web.

That being said, Joinmarket is an awesome project, and perhaps if the privacy.bitcoin.com subdomain were dedicated to facilitating use of Joinmarket, everyone would win. (Except 'Muricans in black helicopters.)

It could be a simple redirect with an overlay of instructions, for instance. Or better yet, contrast and compare the various projects out there like Joinmarket for them to choose from.