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 might be good enough for web passwords, but coming up with your own mnemonics is not truly secure because there are discoverable patterns in anything people come up with themselves, it isn’t actually random. If you order words in such a way to make it easier for you to remember it also makes it easier to bruteforce. Lots of crypto wallets where people tried to do this were remotely drained.
Doing this is only safe if the words are selected with secure RNG of some kind.