chrisella, I’m at the phpbb3 to bbpress converter notes on the phpbb3 support forum and the gentlemen writing the code has mentioned passwords and something to do with MD5 hashing. I don’t know what that means, but there is a link to some coding to correct the problem with passwords. Not sure if that is what you may need, but take a look.
https://bbpress.org/forums/topic/phpbb3-gt-bbpress-converter-beta-release
The password plugin they mention is at:
https://bbpress.org/plugins/topic/md5-insecurity-for-bbpress/
