top 3 lightweight linux distros:
Frugal Install- EasyOS, from the creator of puppy, the bleeding edge of frugality, supports encryption, easily boots from EFI.
Live USB -- Puppy Linux, great app selection, customizable, works great from usb, allows full encrypted persistance.
Full Installation: SliTaz, super lightwieght at only 50mb, works great with less than 1gb of ram, great community. Cons: no encryption, takes some fidlin
Best Overall: Puppy Linux - it does it all, and well