user37515: With no server and only in the browser I'm generating an a bip39 key and giving the user the mnemonic to store some place safe for restoring, I also want the user to be able to login with a password.
1) Could I encrypt the mnemonic with a password?
2) If I do encrypt the mnemonic, which algorithm should I use?

user3697: Bip39 has an optional "encryption" over PBKDF2 (passphrase-to-key) used as salt (this allows possible deniability).
https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki#from-mnemonic-to-seed
The weakness there is that BIP39 uses only 2048 rounds during KDF. Which is easy to bruteforce. 
If you store it in a cloud (or similar), I recommend to do a AES-256-CBC encryption of the mnemonic with a strong password and a strong KDF (maybe use PBKDF2 with at least 30'000 rounds).

37515: <p>With no server and only in the browser I'm generating an a bip39 key and giving the user the mnemonic to store some place safe for restoring, I also want the user to be able to login with a password.</p>

<p>1) Could I encrypt the mnemonic with a password?</p>

<p>2) If I do encrypt the mnemonic, which algorithm should I use?</p>
 3697: <p>Bip39 has an optional "encryption" over PBKDF2 (passphrase-to-key) used as salt (this allows possible deniability).
<a href="https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki#from-mnemonic-to-seed" rel="nofollow noreferrer">https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki#from-mnemonic-to-seed</a></p>

<p>The weakness there is that BIP39 uses <strong>only 2048 rounds</strong> during KDF. Which is easy to bruteforce. </p>

<p>If you store it in a cloud (or similar), I recommend to do a AES-256-CBC encryption of the mnemonic with a strong password and a strong KDF (maybe use PBKDF2 with at least 30'000 rounds).</p>
