http://www.google.es/search?hl=3Des&q=3Dusb+protection+dongle&meta=3D

2008/6/25 Tom=E1s =D3 h=C9ilidhe <toe@lavabit.com>:
>
> Let's say I came up with a very special algorithm, one that would be
> very valuable to sell.
>
> If I distribute it as a binary executable file for something like
> Windows or Mac, then of course people can just look at the machine code
> to figure out what it's doing.
>
> I've been looking into using a microcontroller to keep an algorithm
> private. Let's say I have an algorithm as follows:
>    It takes a 128-Bit number as input and gives a 128-Bit number as outpu=
t.
>
> Now here's what I have in mind:
>    I get my hands on a microcontroller that has either built-in USB or
> built-in Ethernet. I compile my algorithm for the microcontroller in
> question. I produce a device about the size of a matchbox and sell it,
> and the consumer plugs this device into their PC, perhaps into a USB
> port. The microcontroller will take input from the PC, run the algorithm
> and then give output to the PC.
>
> Has this been done before? (Try not to throw plates at me if it has)
>
> I've heard about the "code protect" feature of PIC chips. Does this
> feature prevent the program code from being read from the chip? Is it
> 100% secure?
>
> Lastly, how would you suggest I go about this: USB or Ethernet. Ethernet
> would be handy in that I could set it up as a webserver that takes input
> and then gives the output on a webpage. Another good thing about this is
> that it would be platform independent and would work on anything that
> has a web browser.
>
> USB would be attractive because it's what people are "used to" and it
> seems USB ports are more ubiquitous than Ethernet ports. Also I do away
> with a batter because I can take power from the USB port. How good is
> USB though when it comes to cross-platform development?
>
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-- =

Ariel Rocholl
Madrid, Spain

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