How to protect file on USB from being copied?

How can I prevent file on USB flash drive to being copy and paste either via right click or drag and drop copy to other device that is hookup to it like a PC ? The file will be PDF, document file, JPG or some other image file, and some movie file etc?

The scenario is the file will be needed to be just viewable to show people but they cannot copy any part of it out from it other than admin level that create/authorize full control of it. Example is like a person on a field trip is bring some presentation stored on USB flash drive and show it on field premise to showcase company stuff like brochure, powerpoint, concept drawing, sales figure etc but we do not allowed them to have those file on the USB drive to being able to copied off to client's PC or even their own home without authorization. Not even a phrase or JPG image from a particular document etc. Pretty much just view only mode.

i found in the Amazon, it indeed has such product FYEO copy protection USB flash drive. the link is http://www.amazon.com/FYEO-Partition-Protection-Encryption-Waterproof/dp/B01C5ZIL6C?ie=UTF8&m=A1BZ6154GHMVA5&qid=1462416629&ref_=sr_1_26&s=merchant-items&sr=1-26

http://www.amazon.com/FYEO-Professional-Collection-Anti-Virus-Protection/dp/B01C3P40P0?ie=UTF8&m=A1BZ6154GHMVA5&qid=1462416629&ref_=sr_1_48&s=merchant-items&sr=1-48


In the end, but reading is copying. To "read" a file practically means to "copy into RAM", otherwise programs couldn't work with it. And once that's done, you can't possibly stop every single program from having a "Save As..." or "Copy to..." option.

The same applies even to humans. If someone reads a phrase, they will remember it and can write it down by hand. (Although more likely they'll just take photos of the whole presentation.)

Maybe it would be enough to put watermarks on everything?


It's not practically possible because if someone can read it, he/she can also copy it. Even if you control the machine/computer, they can still capture the photos of the screen. Secudrive offers secured USB drives: http://www.secudrives.com/products/USB-security that is something similar to Amazon copy-protection drive you've mentioned in your question.