They are explicitly a product for user privacy. Given that the depositor can prove the source of funds put into tornado cash via a zk-proof there is no reason that this should be shut down.
That's the facade. In my experience, Bitcoin is still the main ecoin demanded in phishing/ransomware incidents, even when more privacy-friendly ecoins exist. A tumbler's purpose is distorting Bitcoin's public blockchain (one of its core tenets), and that's very attractive to criminals.
Well, it's not banned, but over $10k USD in cash you need to fill out an IRS form 8300 [1] precisely to curb criminal use of cash. (Although I'd argue it should be upped and pegged to inflation as 10k isn't what 10k used to be.)
Wouldn't filing a form 8300 be unconstitutional violation of the 5th amendment if the cash is an element of the crime of both parties? As an example, felons can't be charged with NFA violations for owning a short barrel rifle for example because registering their firearm would be self-incrimination. I believe Timothy Leary also got out of being charged with Marijuana reporting [tax] requirement because filing for the tax would self-incriminate his possession.
I have NEVER heard of any of this. Can you provide any sources?
I think the 5th has been restricted enough by the courts that it literally only matters if you EXPLICITLY invoke it. (At least this is my understanding of Berghuis v. Thompkins.)
Criminals are still required to pay taxes, they just aren't required to list its source (misc entry on income form). Leary's case was won on the basis that the registering provision violated the right to not self-incriminate (and that you couldn't pay that tax without registering).
Similar for the NFA case - they can't get then for the failure to register, but they can still get them for manufacturing/possessing it (especially since it was amended after the ruling).
That's the facade. In my experience, Bitcoin is still the main ecoin demanded in phishing/ransomware incidents, even when more privacy-friendly ecoins exist. A tumbler's purpose is distorting Bitcoin's public blockchain (one of its core tenets), and that's very attractive to criminals.