So I’ve been trying to create more secured passwords now that I have employment where I have responsibility. They require us to change our passwords every 3 months. I used to use the same passwords for multiple sites. Then I used a password manager and got rid of those memory passwords. With this job I don’t want to mix my personal password manager with my work computer and I also don’t want to remember a complicated 15 character long password to log in every day.
That brings me to my question. I’ve been using Yubikeys for years. I store a challenge response, use it for 2FA on all sites that allow, and I use it for TOTP on most sites (there’s a limit to how many entries in the Yubikey 5). You can also store a password in one of it’s two slots. My thinking is this: Is it secure to store a base password that is long and complicated, say 40 characters long with all the characters, and use a different “prefix” for each application? Example: On my banking site I type in “bank” then press the Yubikey to type the rest. Same thing with social media and other accounts. Each one has a prefix and I don’t know the actual password. Of course I store all passwords, including the Yubikey, in a password manager that’s backed up in the cloud (I use KeePassXC).
Your thoughts? Is this secure or stupid?
I may not have been clear in my original post. My work computer does have it’s own KeePass database. This question is for my use of a Yubikey on multiple sites. For clarification I use a separate Yubikey to store my work computer credentials that I back up to my personal Keepass database (can’t access the work database if I’m locked out). I do this because of the requirement to change passwords every three months and I don’t want to reuse the limited passwords I remember so I use a password generator.
My question is with using a “prefix” with my personal Yubikey (the one I don’t use for work). Specifically, even if the last 40 characters is from a generator configured to generate a high entropy excellent quality password if I use that password with a different “prefix” (different lengths too) for different sites then would it really be compromised if one site gets hacked? They are different passwords, different hashes, different entropy. It’s just a large part is the same. I don’t know much about security I just want to know if this is a risk. I’m trying to move my security from something that I memorize to something that I physically have and know.