Unsigned code refers to an application which has not been signed with the secret key required for it to load on a console.
In the video game console business, most console games have to be signed with a secret key designed by the console maker or the game will not load on the console. There are several methods to get unsigned code to execute which include software exploits, the use of a modchip, a technique known as the swap trick or running a softmod.
It may not initially seem obvious why simply copying a signed application onto another DVD does not allow it to boot. On the Xbox, the reason for this is that the Xbox executable file (XBE) contains a media-type flag, which specifies the type of media that the XBE is bootable from. On nearly all Xbox software, this is set such that the executable will only boot from factory produced discs so simply copying the executable to burnable media is enough to stop the execution of the software.
However, since the executable is signed, simply changing the value of the flag is not possible as this alters the signature of the executable causing it to fail validation when checked.
Famous quotes containing the words unsigned and/or code:
“There yet remains but one concluding tale,
And then this chronicle of mine is ended—
Fulfilled, the duty God ordained to me,
A sinner. Not without purpose did the Lord
Put me to witness much for many years
And educate me in the love of books.
One day some indefatigable monk
Will find my conscientious, unsigned work;
Like me, he will light up his ikon-lamp
And, shaking from the scroll the age-old dust,
He will transcribe these tales in all their truth.”
—Alexander Pushkin (1799–1837)
“Hollywood keeps before its child audiences a string of glorified young heroes, everyone of whom is an unhesitating and violent Anarchist. His one answer to everything that annoys him or disparages his country or his parents or his young lady or his personal code of manly conduct is to give the offender a “sock” in the jaw.... My observation leads me to believe that it is not the virtuous people who are good at socking jaws.”
—George Bernard Shaw (1856–1950)