Do you trim() usernames and passwords?

I seem to have an issue with users who copy-paste their usernames and passwords coping and pasting leading and trailing space characters. The obvious fix was to trim() the values that I receive, but I worry how that would affect users who use a space at the beginning or end of their password. Of course, if I trim() also when the user is setting his password then he will never know that his password is really 1 digit shorter, but do I really want to do that? Thoughts? Thanks! -- Dotan Cohen http://gibberish.co.il http://what-is-what.com