I recently tried out a decentralized private messaging tool, it didn’t ask for my personal information to register.
Instead, it only asked me to create a username and set a password, after which it provided me with a mnemonic passcode. (I had never used a mnemonic passcode before, but I learned that it’s a web3 or decentralized type of thing.)
On their FAQ page says “The Mnemonic Passcode is your ONLY SOURCE of backup in a scenario where your device breaks down or becomes unusable due to any reason. In such cases, all you need is your Mnemonic Phrase to recover all your account information. It must be copied, screen-shotted, or written down and kept in a safe and secret place until it is needed.”
Does Mnemonic Passcode more secure than usual password? Plus, is there any other ways to keep you mnemonic phrase?
It is (or can be) just as secure as a non-mnemonic passcode. The mnemonic aspect just helps with typing it out without errors.
You’re not really supposed to remember the mnemonic passcode, but save it in your password manager and/or print it out and store it in a secure location.
Now if you need to use your printed out mnemonic passcode, you just have to type in a bunch of normal words instead of a very long list of random characters and symbols, where it’s easy to make mistakes.
I always thought it is for enhancing security
In enhances security by allowing high-entropy passwords to be easy to remember and write, so you have no incentive to use short/simple low-entropy (insecure) passwords.