orml_unknown_tokens can be target for spam?

[dzmitry-lahoda]

Using MultiCurrencyAdapter to send assets to orml_unknown_tokens::concrete_fungible_balances leads to creating accounts per token per recipient.

So one may send a minimal fee as payment for the first payment asset (as I see there must be paid or unknown tokens lost?).

Can send second assets with random id and random recipient and use big storage because ED is not taken for this.

What can be done?

For example, store assets on the sender chain account and restore assets using historical data from somewhere (not automatical).

Of may take ED from asset fee ?

What happens if the sender sends a token and no fee is provided at all? Do unknown tokens fail fully? Could at least store assets on account if chain sender?

[xlc]

It is a known issue paritytech/polkadot#2702