I need the default security code for kdc-325

Your best bet is to contact Kenwood support either by going online to: http://www.kenwooduse.com/contact or by phone at: 1-800-KENWOOD (536-9663). Be prepared to provide them with the serial number of your unit. If your code was changed from the default, you may have to perform a reset. It requires one of the following procedures. Type 1
During the code request mode, while holding the DISP key depressed, press and hold the Volume UP or DOWN key for 3 seconds (so that “…” disappears).
Then using your remote enter your code. Type 2
Press the "Auto" button and "Track up" on face of radio at the same time. The four dash lines ( . . . . ) should "disappear". Then using your remote enter your code. Type 3
Model# DPX-4020 and DPX-4030
Press and hold the 1 then the 6 preset key (preset keys are the buttons on face of radio for storing you "favorite" radio stations). "C" should display.
Then using your remote, enter your code. Enter your number from the remote control unit. Your code number is 5227 (KCAR) * Press numeric key “5” ( 2 times ) and press the Track UP/Next Track key
* Press numeric key “2” ( 3 times ) and press the Track UP/Next Track key
* Press numeric key “2” ( 1 time ) and press the Track UP/Next Track key
* Press numeric key “7” ( 2 times ) and press the Track UP/Next Track key The security is canceled and the set enters the TUNER mode! when finish all the procedure, is necessary to press "TRACK UP BUTTON" for 3 seconds.. and youre done.