In a hypothetically perfect world, we’d be able to remember infinite numbers of passwords. However, for most people that’s not possible. Instead we have to find a way to make best use of that limited memory. Here’s how:
- Do not use passwords that are easy to guess, e.g anything directly related to you, like your name or names of family/friends/pets/etc; or date of birth; or favourite colour,band,etc..
- Ideally, use a longish random string as your password, of at least 10 characters (but longer is better).
- The same applies for password-recovery questions, which often ask for information that is in the public domain (e.g. mother’s maiden name, date of birth). Do not provide real answers! Instead just make something up, or use another random string if possible.
- Do not re-use passwords across different websites, unless you truly do not care about what is on those sites, and what they can do in your name with that password.
- Do not be afraid to write them down if you can store them securely. E.g. if your home is reasonably secure, it’s fine to store most passwords on paper there. This goes against advice from many well-meaning, but utterly-wrong “experts”.
- If you trust that a computer or device is sufficiently secure, it’s perfectly fine to store passwords on it, e.g. in a text-file. Also, many programmes support saving passwords and if you trust those programmes then it’s perfectly OK to use those features.
- Consider using disk-encryption products like PGPDisk, TrueCrypt, BitLocker or the built-in capabilities of many Linux/Unix distributions (some of which offer this at install time) to protect your data with a master key. This is particularly recommended for laptops.
- Any computer running Microsoft Windows likely can not be considered secure and should not trusted with more sensitive information. Portable devices should not be considered secure, unless their contents are known to be encrypted, and they automatically lock themselves after a small period of unuse (i.e. don’t trust your phone too much for storing sensitive data).
Basically, in an ideal world, all your day-to-day passwords for your various, online accounts should be unguessable, random strings; you’d never have to remember any of them; you would just, at certain times, have to enter a master pass-phrase (which should be unguessable, but still memorable and much longer than a password) without which the passwords would effectively not be accessible.
Remember, security is a compromise between convenience and consequence. The ideal level of compromise will differ between different people, and between different situations. E.g., obviously, it’s probably a good idea to tolerate a good bit of inconvenience with your online banking login details and commit these solely to memory. If you have too many accounts to memorise the details, then store them very securely, e.g. buy a strong box or small safe, and obscure which details belong to what accounts – hopefully this buys enough time to contact banks and have the details changed if your house is burgled and the box stolen.
Common sense goes a long way. Unfortunately the “experts” you sometimes hear from don’t always have it.