In Hudson only admins can add new Subversion authentication entries via the scm/SubversionSCM/enterCredential page.
For Hudson setups that host many job's for many different projects, this is to strict. In this situation project members (non-admins) must be able to enter their own authentication entries for their projects subversion repository.

A solution would be to extend the Project-based Matrix Authorization Strategy with an option 'Configuration' in the SCM column.
So for each user/group row it can be decided if it can configure scm details like adding Subversion authentication entries.