What is the strongest encryption of password Jradius can support?

Sample client that I wrote on Solaris using JRadius APIs is able to get authenticated from a FreeRadius server running on Linux. However, the password was passed as clear text? What is the strongest encryption supported in JRadius for password encrypting / hashing? Is there a document that I can refer to for settings required in FreeRadius server and APIs that can be used in JRadius? Thanks, Rama