The first time you connect an unlocked iDevice to a computer and run the iTunes software, a pairing/sync certificate, known as a lockdown certificate, is created on the computer's hard drive. Depending on the operating system in which iTunes is installed, lockdown certificates are stored in the following folders:
C:\Documents and Settings\[username]\Application Data\Apple Computer\Lockdown
In older version of Mac OS X lockdown certificates are stored in
Within these paths, there is a lockdown certificate for each device that was ever ...