Topic: [ANN] ChipMixer.com - Bitcoin mixer / Bitcoin tumbler - mixing reinvented - page 29. (Read 92822 times)

Clearnet site working?

Clearly there will always be more smaller transactions of a certain size than bigger transactions.
But you can easily deposit a big value and withdraw a number of smaller chips.
And you can easily deposit a non-standard value so it's not seen as a deposit to CM, but of course, this means that you also make a donation.

I would argue that using a bigger chip has a positive impact on privacy, in some situations.

If you spend two chips of equal value, someone looking would know that you sent the chip value to CM on or before each chip was created. With a single, larger chip, someone looking would know you sent the chip value on or before the date the larger chip was created.

If someone knows all transactions going to CM, the list of transactions that meet the criteria of using two small chips is going to be smaller than using a single, larger chip.

The caveat is using a single chip that is larger than necessary. If you use a very large chip that results in a large change amount, it may benefit your privacy to rather use several smaller chips, depending on the circumstances. 

Making several deposits to different addresses in a short amount of time still reduces privacy. That's why ChipMixer uses vouchers: you can keep them for a long time to make it much more difficult to link your individual inputs.

Can you share your findings?

That makes sense, to a certain extent. If you have to pay something that can't be paid from one chip, you add another one. So if you have 12 chips and need 3, you only use 3 and leave the remaining 9 untouched.

It's hard to say: If you deposit exactly 0.512 BTC, get one chip, and spend it the next day, it's possible to link a list of possible inputs to possible outputs. But you could just have well deposited a much larger amount, or several smaller amounts (through the use of vouchers). You can also have months or even years between creating and redeeming the voucher. An observer can guess and make assumptions, but without additional information they can't know for sure which input belongs to which output.

Thank you

Yes, i'm aware that this decreases privacy. I'd be great if you could generate multiple deposit addresses during same chipmixer session.

I also ran blockchain study on spending  chipmixer transactions and there are two interesting things i noticed:
- Most people, like 95%+ are combining the chips while withdrawing them. They do not withdraw/spend each chip to separate addresses.
- The 0.512 and bigger chips have very few spending transactions. The difference is very significant significant. 90% of spending transactions involve smaller chips

Data from 5-6 days of blockchain transactions.
Number of spending transactions involving given chip size

0.032 337
0.016 676
0.064 200
0.256 67
0.128 94
0.512 39
1.024 22
2.048 21

Based on these numbers, does using bigger chips due to fewer transactions seen on blockchain, have any negative impact on privacy?

True. It seems their policy changed between November 2020 and August 2021 without notice.

I don't know, I just found it in the FAQ a while ago.

I remember reading that too earlier.

When did this change? It used to be the case that sending 0.0015 BTC twice would result in three 0.001 chips.

Yes.

It's in there, although slightly hidden:

I suspect it'll just check for the confirmation of the first transaction. If they aren't included in the same block, it may just pass the second. However, it is nowhere stated that you have to send your amount in one transaction. There's no answer in FAQ, so only @ChipMixer can enlighten us.

The real question is:  Why do you want to send multiple transactions funding the same ChipMixer address? Why not redoing the procedure with a new deposit address for the second transaction? For the sake of your privacy you shouldn't reuse addresses whether they're yours or not.

Is it possible allowed to send multiple transactions to deposit address generated by chipmixer? Or should it be one transaction?

Yes.

You can withdraw those too.

This is (still) in the FAQ indeed:

I assume this is (very) outdated now, and left over when fees were very high years ago.

Yes, you can withdraw 0.001BTC, but that's the smallest amount you can withdraw.  If you send 0.0025BTC to your mixing address you will be able to withdraw one chip for 0.002BTC, or two chips for 0.001BTC.  The 0.0005BTC will be donated.  If you send 0.0019BTC, you will only be able to withdraw 0.001BTC.  

For additional privacy it's not recommended to send multiple transactions to the same mixing address.  If you do however, you will not be able to combine the dust, it will be donated.  For example sending one transaction for 0.0016, and another for 0.0014 to the same mixing address will allow you to withdraw 0.002BTC.

Let me ask it a different way, maybe it's just bad English in the faq. Are you able to withdraw the 1 mBTC chips? What about the 2 mBTC chips?

The website implies you cannot. "Instead of withdrawing small chip - we issue a voucher for that amount. You can redeem old voucher to merge two small chips into one bigger and withdraw big one." The smallest chip is 1 mBTC so this implies you cannot withdraw them but would need to combine them into a larger chip for withdraw.

It's actually listed at the very top of the exact same page ^{[under the "How does deposit work?" part]} and it's 0.001BTC:

• Quote from: https://chipmixer.com/faq
  Minimum deposit is 0.001 BTC - lowest chip size. If you deposit less then you have to deposit missing amount to receive a chip.
  Second minimum deposit is 0.002 BTC. If you deposit between 0.001 and 0.002 BTC you will receive only 1 mBTC chip and rest will be autodonated.
  
  
• Update:
  I forgot that's also listed on the latter part of that page:
  
  
  • Quote from: https://chipmixer.com/faq
    What will happen if I send less than lowest chip?
    Since we don't have chips lower than 0.001 BTC, your deposit will be treated as donation.

The FAQ states you "cannot withdraw small chips" but I can find nowhere that defines what a "small chip" is. What is the minimum withdraw size?

v3 version message is old. It should be removed.
If your voucher does not work - contact support.

what is the current state with v2 vouchers?

v2 version says they're valid on v3
v3 version says "Old vouchers will be available at Segwit version after few days"

...
Nevermind, was an electrum error

When someone deposits bitcoin to their service, they must withdraw within a certain time by obtaining a private key for the various chips they have. Once a private key has been given to a user, CM knows that chip is no longer available and can update their database. When someone withdraws a chip, they will not necessarily spend the UTXO immidiately.

CM can periodically create new chips in a number that is approximately equal to the amount of chips that have been withdrawn. They can also estimate demand for their chips based on current account balances, and use their profits to create additional chips of certain sizes.

Generally speaking, it will never be a secret that a particular UTXO is from a particular mixer. Blockchain analysis companies will use mixers to trace that mixer's UTXO set.

From the looks of it, chips do not stay on CM for very long. One tx that CM used to create chips was 9146153f9c90075d781c3ac798472648f36e9849069a57e26206b9ca40e86e8f (12/27/2020) and the first output address was 1Mte55HMcubh11MNfKNk7C6mXjWnHj7vX It looks like whoever received this chip also received several other chips:
17c5d8ZpsEthDRaZqsCryM5kHqy1Vbc3cq ‎0.03200000 BTC (1/30/21)
14b47PAmGKsEGrvoZ9LpQdSvQbdKQ6QafJ 0.00200000 BTC (1/26/21)
157jeJakzkK18sayYsyfxKCGa8U1zrmPnb ‎0.01600000 BTC (1/31/21)
19xFcK3CLkUEBAC5PTfNHQN2rcEueFBexu 0.00200000 BTC (1/25/21)
1NQHAzip6EA3hBFjKPKgZTsvuKQmAW2pfC 0.00200000 BTC (1/27/21)
1Edu9FAbZXCFq3KXM5jgd4p2J1A1pSn9ci ‎0.01060600 BTC (1/7/21)
15GMbRgb63mYxBosA1CsKbTir9cNTDggjr 0.00008700 BTC (1/30/21)
16WgyvtAECWtDw4PpEqTQD8JYZ8y73pAyt 0.00800000 BTC (1/27/21)

The transaction that spent all of the above chips 186c9c1f6f6cd7b15a81c5836852fc3206e441583902adda18ad7a51242afe9c was confirmed 2/2/21. Whoever received the above chips cannot have received them prior to their funding date (noted above), nor after when they were spent (2/2/21). It is possible this person received chips from CM over time. I would say that the above transaction suggests CM holds chips for somewhere between 2 and 8 days before giving them to a customer.

So CM is creating new chips at a rate of at least once per week. Again, you should not expect the fact that you have a UTXO from CM to be a secret. Each of the above chips was funded with a transaction with exactly 20 outputs, all of which are exactly of the same amount (there is no change address).