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In short: blindmixer works both as a mixer and a wallet, but should really only be used as a  wallet to facilitate the former, given that blindmixer is fully centralized. blindmixer uses blind signatures to ensure that your inputs and outputs are cryptographically unlinked. Even we do not know which inputs originally belonged to you when you withdraw!* No other centralized mixer does anything close to this currently!



Apart from provable privacy we offer some additional unique features, most of which we can offer because we are a centralized entity:

• blindmixer utilizes in-house coin selection algorithms, allowing us to not only batch transactions at scale, but we are also able to make the smartest* choices when selecting inputs.

• blindmixer brings lightning to the average Joe. No longer will you be required to set up your own node, or use a separate wallet for your lightning transactions. blindmixer allows you to pay and generate invoices from the comfort of the same wallet.

• blindmixer is provably-honest. We will be unable to get away with duping any single person.**

• blindmixer offers their service at cost. Apart from very limited anti-dusting fees, all of blindmixer's services are ran at cost. There are no hidden fees.***

• blindmixer allows instant and free transfers between users.

* In comparison to the standard core selections.
** Every action both by the user and the custodian that involves funds requires a cryptographic signature, thus proving the intent of both parties at all times. Example: the user signs a claim-request (claim-request: request for (blinded) coins) for a hookin (on-chain deposit) with the public key of the address the hookin was made on.
*** blindmixer wipes the custodian at set intervals. This is both to make
A. money,
B. exit scamming less lucrative,
C. exploiting vulnerabilities less profitable.

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What are the drawbacks?!

• blindmixer is still a custodial and centralized mixer. Through malice, error, or other causes, your funds* could potentially disappear at any given time, without you being at fault. *Your funds as in the collective of all of the users of a custodian. we previously explained it would be impossible for us to dupe a single user without it being proveable!
  

• blindmixer is a complex object. there may be unspotted vulnerabilities in the code which can cause a loss of funds, especially in the first few iterations. Be wary that any funds you deposit can be lost at any time, as we are too. There may be trivial exploits in the custodian code that allow for a complete draining of the custodian, such as a missed signature check.

In what scenario would I use this mixer?

We think blindmixer is to be fully appreciated when used as your day-to-day wallet. Used correctly, a transaction costs as little as a regular input. And that's not even mentioning the ease with which you can use our lightning services to pay for any service or everyday goods, all while retaining full privacy.

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FAQ:
 Why should I trust you with my bitcoins?
   - You should not. Everyone needs to assess the risk they're willing to take with their coins, and we hope we offer enough to make it worth it for you to take that risk. There is no compelling argument we can make as to why we are worthy of safe-guarding your coins, because really, we aren't.

For more frequently asked questions, you can visit our FAQ

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How exactly does blindmixer work?

In technical terms: blindmixer takes the bitcoin you deposited, and returns to you a claim to a set of coins equal to the deposited amount. Only you have the keys to those coins, and you use them each time you want to make a transaction. Due to how blindmixer works, we do not know your coins, nor the keys. We only know whether or not they are valid, and whether you are the actual owner of them.

For more detailed information, please check out: Overview

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How to use:

Step 1. Visit mixer.blindmixer.com

Step 2. Choose a custodian.

Step 2.1 Choose both a password and a name. Save your password and mnemonic phrase!

Step 3. Deposit bitcoin through either lightning or a normal transaction.

Step 4. Start mixing!

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Electron
blindmixer also offers an electron shell, should users be interested in using that. We think it could be of benefit to both your privacy and security.

For more information, please visit Releases

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Source code

For those interested in the source code, our github repositories are publicly accessible. You are welcome to contribute or point out bugs.

For those who spot critical security vulnerabilities; please PM us here on bitcointalk or send an email to our support. No monetary compensation is guaranteed, though it is highly appreciated!

blndmxr-mixing-wallet
blndmxr-lib
blndmxr-wallet-electron
blndmxr-custodian

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If you still feel uncomfortable, get a feel for the wallet by using our testnet custodian:



Rollover date of both custodians:


Our pgp key:

Latest wallet file as of 2021-09-26

Verify the checksum using
Or verify using the signature on our website (note: you can't directly copy this, please see https://blindmixer.com/releases)
Once downloaded:

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Commonly asked questions:

A. You use cloudflare, isn't that bad for my privacy?
Answer: Only if you weren't using blindmixer properly to begin with. If you do not use a different ip between asking for a withdrawal and asking for acknowledgement of a deposit, we will most likely be able to link your in- and outputs together. As we see the custodian as the primary attacker, preventing this secondary attack vector on your privacy does not interest us greatly.

Why?

Because we do not want you to require any *blind* trust* in us in the first place. Removing cloudflare would probably have the opposite effect: users will more often than if we didn't remove cloudflare trust us to not log their ips, which is bad given that we CAN log it, undetectably. It's a good rule of thumb to expect that anything that can be logged will be logged. And so removing cloudflare does nothing to prevent us from logging your ips, but instead give some users a false sense of security, especially those who do not assume that the custodian is "evil", which is something you should always do. And so removing this vector while leaving the primary attack vector in place (us) does not make a whole lot of sense given the benefits of cloudflare.

*Again, some level of trust is required, but where trust is required, you can verify that we are acting honestly, until we are not in which case it will become apparent and proveable. This is not the case for logging ips, as you will never be able to prove or disprove this, so you should never trust us not to log it.

Keeping cloudflare in that regard might actually promote privacy, or at least make users more acutely aware of the lack thereof.

B. You speak of tor so much, yet blindmixer does not work in the tor browser?
Answer: Indeed. the tor browser does not give us (as far as we are aware) sufficient access to instances such as indexeddb, which are required to properly store data related to your coins such as signatures. The very nature of the tor browser (amnesiac) does not make it a prime candidate to be used in combination with blindmixer, as you'll have to restore your coins each time you close your browser. (both takes a long time and can easily deanonymize your inputs/outputs)
It will also not work without javascript, as we do all the signing to ensure fair communications client-side. You can however use any of our electron builds, or route traffic through tor on your regular browser.

C. How do you make money?
Answer: We wipe the custodian every so often. This means that all the funds that are still present in the custodian at that moment in time, we claim for ourselves, and the signing keys will be regenerated. This has some significant advantages:
I. We can run our services at cost. II. We are disincentivized to exit-scam. III. Other users are disincentivized to exploit our software (and more likely to report it for a share of future profits), as there'll be less funds present than if we weren't to rollover given that over time there will be a set percentage of users who will forget about their wallet, not care, or are otherwise unable to access it.

In your mixing wallet, you can see exactly when the wipe is scheduled for your custodian (https://mixer.blindmixer.com/, once logged in head over to "FAQ"), and we also mention it above (see: Rollover Date)

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Currently known issues:

• Custodian can dupe people who try to recover their lightning invoices by telling them they don't exist or don't belong to the claimant. However if you have a locally stored copy of the invoice this will be trivial to prove, so in general it would not be in our interest to claim this as we don't know whether you have a copy or not. (thus making it possible to prove the custodian is acting dishonestly)
  

Please ask us any and all questions you might have! We're just as curious as you! Try us and let us know what you think!