Hash auth key with Argon2id, encrypt protected private keys with the result.

[9876691]

See this article.

https://dchest.com/2020/05/25/improving-storage-of-password-encrypted-secrets-in-end-to-end-encrypted-apps/

In the event of a server breach make brute force memory hard and make sure attacker has to do full brute force not just brute force of password + 1 decrypt.

We will need to store the seed for the argon so that we can reproduce the key.

Problem how do we get the master_key_hash for the decrypt page.

Store in encrypted cookie?