Question says it all. We are designing a system where security is very important. One of the ideas someone had was to force users to change passwords every 3 months. My take on this is that while its more secure because the password changes often it also forces our users to remember ever changing passwords and makes it more possible that they will just write it down somewhere to help remember.
In the same idea is it really good to force users to use a super hard to guess password. Force them to use ?%&% and uppercase lowercase letters. I know its quite the hassle to invent such a password and then remembering it.
Then again we do not want anyone using 12345.
So. Is there any whitepapers about this subject? Good practice?
I am talking about a website created with PHP. MySQL in a lamp environment if that changes anything.