[zaejcdcy] Single sign on

The advantage of single sign on is you can have a long secure password or passphrase that only needs to be typed infrequently.  The disadvantage is less repetition makes it more likely to forget the password.  What frequency of password typing is best?

Realistically the solution probably involves computationally expensive PBKDF like Scrypt.

One can do ad hoc single signon by storing passwords for different services on a key ring which is unlocked by a single master password.  Many people and products already do this.  We need more uniform ways a web app can interact with a wallet.  However, we also need to support the many additional ways and steps of authentication, e.g., 2FA, some of which don't even exist yet.  Such key ring systems also seem fraught with cryptographic dangers.