Grin [1] requires interactivity between both parties to transact.

1. Https://grin.mw

This is a consequence of Grin implementing the so-called Mimblewimble protocol. Quoting from [1],

> In Mimblewimble, outputs are Pedersen commitments r*G+v*H which combine value and blinding factor into a single curve point. The blinding factor serves both to hide the value and to control ownership. Correspondingly, a single (multi-)signature serves both to prove value balance (non-inflation) and to authorize transfer of ownership.

[1] https://np.reddit.com/r/CryptoTechnology/comments/kyhgcv/are...

> There is no mechanism in crypto to reject incoming funds

Couldn't the same be said of a regular bank account? This doesn't seem to be unique to crypto.

Targeting the most prominent wallets may garner a bit more attention but the end result seems the same. A large number of individuals can have tainted funds deposited in their accounts creating a logistical nightmare.

Your bank has the ability to reject the funds (and some banks will allow you to broadly control deposits with a credit block).

Before posting funds to your account, a bank will scan the funds transfer against sanctions lists and only allow the deposit if there is no hit.

You don’t think someone on a sanctions list attempting to transfer funds to an account holder is going to cause them a problem, regardless of whether it’s blocked?

It's even funnier when you can create a token with any name you want and send it out...

And it's hilarious when they have to pay you to get rid of it.

Ethereum accounts don't own tokens in the same way they own ETH. Token balances exist with smart contracts, so when someone sends you booby coin all they are doing is updating the storage in a smart contract that 0x123 owns 1bil booby coin. Indexers like etherscan parse all transaction events and just keep a tally of what smart contracts have your address listed in balances.

By paying to get rid of it all you are doing is paying for etherscan to update its backend that your address is no longer listed in that smart contract. The real solution is to have wallet software that only tracks tokens you care about.

The chain I did it on allowed me to set a levy that would go to my account every time the token was moved. I hate that stupid coin.

The fact that none of the popular crypto projects have this mechanism just goes to show that nobody was thinking all that deep about the human level of it.

The very existence of a clear transaction history on the blockchain is the root of all problems. If everything is natively encrypted by zero-knowledge proofs or ring signatures, none of the issues - privacy and chain analysis, the possibility of tainting a coin, the appearance of centralized coin-mixing services with questionable security, and the numerous aftermarket privacy tokens and coin-join protocols - would exist. The idea of a privacy-preserving digital cash has been proposed since the 1980s, unfortunately this property is not found in many major cryptocurrencies.

If there was a coin in which it wasn't observable whether you were interacting with a sanctioned entity, it wouldn't make it any more legal to do so. If it shared the same issue of allowing unsolicited transactions, the same problem would exist.

Even if said coin existed, it wouldn't guarantee privacy, because information about transactions can be recorded or observed off-chain, and that information can be compromised.

Monero and Zcash are legal.

I never suggested anything that would contradict that.

Monero is definitely a better option for anonymity, but most crypto users these days just use centralized exchanges. I doubt the government will take kindly on people cashing out any anonymous currency regardless of your legitimate purposes.

So cash is illegal?

As long as the government can print as much as they want then no. Cash is only partly anonymous but is still a safer bet than a lot of crypto if you are trying to achieve reasonable anonymity.

> Cash is only partly anonymous but is still a safer bet than a lot of crypto

I strongly agree. If I have a choice between paying in cash or in a cryptocurrency, I would choose cash nearly every time (with a few exceptions).

Zerocash is now shielded by default (https://electriccoin.co/blog/new-releases-to-help-enable-zca...), does that count?

Zerocash is an academic paper and early implementation from a group of researchers -- a proof of concept of using zero-knowledge proofs to add privacy to a public blockchain ledger.

Zcash is the ongoing project based on Zerocash, started in large part by those same researchers, but with funded teams of engineers continuously iterating on the protocol and implementations.

It certainly counts as progress. The main criticism to Zcash used to be that 90%+ of the transactions were transparent.

Zcash seems interesting to me in that it feels like Bitcoin without either ossification or getting overwhelmed into becoming a casino substrate like programmable currencies. It evolves but slowly and in a particular well scoped direction.

Several crypto projects were in their own right political statements about taking back control and decentralizing institutions. I'm sure there are government-approved enterprise crypto projects out there that are happy for you to use their services, but a lot of developers especially those that work on things for free are more interested in the mindset of who cares if someone sends me free money. You don't see the GNU or similar licenses putting in restrictions for sanctions for a reason.

I don't think we're talking about the same thing...

> Several crypto projects were in their own right political statements about taking back control and decentralizing institutions

If these projects are about taking back control, why shouldn't I as a user have the agency to only accept transactions I approve?

What if someone dusts you NFTs with abusive imagery on IPFS linked to them? Or spam/scam tokens with funny smart contracts that trick you into doing something you don't want to do when you visit their project page?

It ought to have been an obvious feature from the beginning. Spam and public addresses have gone together since forever.

Bank accounts don’t have this mechanism as well, what does this show?

My neo-bank (Revolut) has this feature. If someone sends me money for the first time, or isn't in my contacts, they have to explicitly accept it from their app before it actually lands in their account.

Ignoring that specific feature, if you did get money sent to your traditional bank account, you can always contact your bank and tell them you don't know what it is to avoid any trouble. This is not possible with Ethereum.

Banks reject all transactions from sanctioned entities.

Banks don’t just allow you to reject transfers from sanctioned entities. They force you to.