If not, how can i do it? Thanks!
fcl and the js-sdk dont ship with any crypto libraries. There are already lots of crypto libraries out there, Node even ships with some underlying crypto functionality. Lots of these libraries also don’t work particularly nice in the browser.
People also have lots of opinions on how to do/implement this stuff and Flow just by itself allows for (I think at this time) 4 different curves and 4 different hashing algorithms, so its a fair bit of bloat for a very small sub-set of users, who should take dealing with private keys extremely seriously and thoroughly understand and audit everything regarding it, especially if they are acting as custodians for their users value.
Instead what we provide is the ability for you to hook into and have access to the data you need at the time something like signing happens. This is done with what we called an Authorization Function
There is nothing special about how Flow deals with keys. Any way that you can generate a key that uses a compatible curve will work with Flow.
If you are going to be acting as a custodian and holding keys on behalf of your users we strongly recommend using a third party that specializes in securely holding keys like AWS KMS or GCC CKM. These secure key management systems will have their own way of generating keys and acting with them.