Securely encrypt stored private keys

[iov-one]

Securely encrypt stored private keys

[will-iov]

OK good. I believe Argon 2 is current best practice for key derivation: https://www.owasp.org/index.php/Password_Storage_Cheat_Sheet#Leverage_an_adaptive_one-way_function

[will-iov]

How do you see using scrypt and secretbox? Is the idea to store the private key in a retrievable form, or just to verify that the user knows it before unlocking an account?

[ethanfrey]

Scrypt as derivation function from passphrase to encryption key. Secret box then symmetrically encrypts with that key. You cannot recover the key without passphrase. Scrypt (bcrypt, pbkdf2...) help avoid some brute force attacks. A similar setup is recommended in NaCl secretbox. 

[webmaster128]

Argon2 in the browser is pain in the ass. It is 8x slower than the argon2 command line tool and in order to be able to use some okayish-secure parameters, we need to create a WebWorker where it can run for a couple of seconds. But I think this is still the best thing we can archive given the limitations of WebAssembly.