Password complexity check

[seralepo]

Hello! What do you think of implementing some type of password complexity check?
For example, for new passwords check length, presence in a dictionary file, and some kind of entropy. Or you think this UI is not the right place to make these kinds of checks? Thanks in advance!

[zgz]

pattern="^.(?=.{12,})(?=.[~·!@#$%^&?()-=_+[]{};':,.?]).$"