Is there any way to generate HD wallet based on username/password combination only?
I understand that I can easily generate and recreate the wallet in a deterministic way based on a mnemonic phrase (eg. with ethereumjs-wallet), but I don't want to make the user remember the mnemonic phrase nor do I want to store anything sensitive on the backend side like private keys (even in an encrypted form).
Each time the user logs in with his username/password I would like to be able to recreate his HD wallet entirely browser-side based just on username/pass.
I could imagine running PBKDF2 on the password with username as salt and using that as an entropy for entropyToMnemonic() from bip39 - could that work?
Is there any other solution?
EDIT: the user will be able to get and backup their mnemonic, but I cannot ask the user for mnemonic to recreate his wallet as it is going to be happening on each login, so it is unacceptable in my use case in terms usability