If your input is a key and not a passphrase, you can just use a regular KDF. PBKDF2 is a waste of clock cycles. Also, your site still says "E2EE" on the homepa

If your input is a key and not a passphrase, you can just use a regular KDF. PBKDF2 is a waste of clock cycles. Also, your site still says "E2EE" on the homepage, you should remove that.