I'd like it if there was a centralized shared secret system available from the following sources: my credit union, my local & state govt, and the fed govt. I'd like to be able to set an arbitrary K-of-N recovery with an additional S "individual" recoverers. I don't mind it being publicly available (it's encrypted!); maybe 16KB for the whole account?

This is because it'd be a way for people to establish identity: let a third party write to my shared account, and I can prove I own it by decrypting the message.

The govt aspect is to prove who I am & establish residence for things like voting, DL#s, birth certificate recovery, passports...