Protecting Source Code

[Paul Rubin]

"John Wilson" <tug at wilson.co.uk> writes:
> There are several solutions. One that I have used is the Dallas
> Semiconductor Crypto iButton (http://www.ibutton.com/ibuttons/java.html).
> The private key is held on the tamper proof token and *never* appears in the
> memory of the computer. The decryption occurs on the iButton and the
> cleartext comes back. The button can be programmed to destroy the private
> key after a set date, it runs its own clock off its own internal battery.

Yes, but once the attacker has obtained the cleartext, s/he doesn't
need the private key any more.  You're better off running the entire
application inside the button.