Encrypt/decrypt private key for localstorage

[kranthicodes]

Problem

When someone creates / Imports a wallet with phoenix app, we currently store their private key in localstorage so that when they revisit the app, we can show their wallet using the private key. But this is not safe though we store it in user's machine and would need to be encrypted followed by password based auth mechanism flow similar to phantom or metamask.

Research

https://stackoverflow.com/questions/28364430/best-way-to-store-private-crypto-key-in-browser#:~:text=You%20should%20use%20a%20symmetric,e.g.%20second%20layer%20of%20AES).

https://crypto.stackexchange.com/questions/35530/where-and-how-to-store-private-keys-in-web-applications-for-private-messaging-wi

[kranthicodes]

will keep updating this issue as i find more ways to do this