I recommend checking the local banking regulations in Muslim countries, as well as their policies on profit, loss, and interest. My understanding is that bank accounts must not be interest bearing and that stock markets are not allowed to make more than a 10% loss.

In turn, this produces oddities as far as cryptocurrencies are concerned. Simply holding a cryptocurrency earns neither interest nor incurs a loss in many cases (there are exceptions to this rule, and you would need to examine the crytocurrency that you were interested in carefully, Proof of Stake currencies pop to mind.) It is only at the point of sale that other factors come into play, and you would have to consider if it would be Halal to sell at a greater than 10% loss, or to simply hold; at which point the token itself can essentially be considered unchanged. Selling the token as though it as an object for a profit would not be considered as earning interest, for example, as that is simple commerce.

However, these are only my observations, there will be inaccuracies and I recommend that you research this topic more carefully than relying on incomplete past information from my memory.