Passwords for Events and Galleries are non case-sensitive.
Every collection must have a password, however you may change the access rights in your collection to "Display with auto-login", in which case visitors will not be asked to enter the password to view the collection.
Your password can have any number of characters, letters, numbers or a mixture or both. We would advise you to use a memorable password, without spaces, that can not be spelt in multiple ways (e.g. won, one, 1) .