Hi @revo!
We're using dHive and it works perfectly so far.
For other crypto operations you can use react-native-crypto module instead of Node's crypto.
In the case you want to use another module that itself refers to Node's crypto it gets more problematic but you can use Babel to change the requests (ref. here). I am currently trying to implement this on another project but it's a bit hacky.
You can check the mobile Keychain code in here for more insight.
EDIT :
Just managed to use a Node module using crypto on RN actually, this comment is especially useful.
Thanks for the links @stoodkev. I check all those out and see what I can make happen.