Q: Old IPOD touch shows encripted on I-Tunes, Never encripted it?

I have and older IPOD touch (last fermware update 5.1.1) last time I updated it I noticed that I-Tunes showed the backup was encripted.  I never encripted it.  I also have an I-Phone 4s and it does not show encripted?  I tried to unencripted it and it wants a password?  Since I never encripted it I don't have a password.  Is there any was to unencript the I-Pod backup or to retrive the password?

I tried every password I use  (abour 150) and it told me none of them worked?  I have a password valt and always put passwords in that valt after I set them.  This makes no sense to me as the valt does not show any passwords for the IPOD touch except the 4 diget sign in code.

I am running a Microsoft Windows 7 Professional operating system.  It is a 3.6 GHz 7 processor chip with 16 GIG'S of memory.  (Not sure if that will help or not?)

Help!!!???