Auth is just important as how the the key is stored, especially when delegated or distributed custody is involved. 

One lesson we’ve learned is to handle all user verification requests within an enclave

What do you guys think about enclaves?

Co-Founder of /0xpass -  https://passport.0xpass.io - programmable key management | Love all things product and design | Prev - Stanford, Microsoft

Enclaves is definitely a secure computing. But there could be downsides of scalability and cost associated with making it operational. 

On the other hand distributed MPC setup like Torus network or DFNS seems like a decent solution considering tradeoff of scale-security-cost

Torus works on 5/9 distributed nodes which independently verifies users access to the key and provides the share. Under a legal scenario where the 5 parties don’t collude seems like a decent solution for delegated custody. Definitely not the ENTIRE CUSTODY!

Torus isn't MPC is it? I thought their MPC offering was 2 of 2