[web2py] migrate passwords from phpBB

[thodoris]

I am trying to migrate users from phpBB whose passwords have been encrypted 
with php_pass. There is a python module that mimics the functionality of 
php_pass and i am wondering what is the best way to override the default 
encryption of web2py. 

Is it sufficient to override CRYPT() using something like:

db.auth_user.password.requires = MyCrypt()

Thanks