These recent inventions are one of the neo-anarch's nastiest tools used to fight the government and corporations.  As far as sources can tell, only one has ever been used, and the use of this device was covered up to keep the masses feeling secure in their system.
        These devices look like any other credstick, and can be of any type.  However, when any device used to check the information on these sticks connects to the network, the stick uploads a virus, and if it is successful it makes all credstick checking devices connected to that hub of the network inoperable. The virus also causes all of these checking systems to display one message of the owner of the black credsticks choice.  Neo-anarch's suggest you use this message to spread information of government conspiracies, corporate wrong-doings, etc.
        These devices have two ratings, a virus rating and a stealth rating.  The virus rating is used in an oppossed success test against twice the level of the device used to authenticate the credstick.  If the virus beats the system, the system crashes for a number of hours equal to the rating of the virus.
        The stealth rating is used in order to avoid getting caught with the black credstick.  The stealth rating is used in an opposed success test against the rating of the device used to authenticate the credstick. If the black stick beats the authenticator in the stealth test, the authenticator will bring up whatever information the black credstick contains as being the information on the network, regardless of whether or not the virus crashes the system.  If the stealth test fails, the system brings up all sorts of tamper warnings.
        The cost of the black sticks are as follows: (in Nuyen)

cost of Stick =(cost of virus rating) + (cost of stealth rating)

cost of virus rating
         level (1-3) =  500 x Rating
         level (4-6) = 1000 x Rating
         level (7-9) = 2000 x Rating
         level (10+) = 5000 x Rating
cost of stealth rating
         level (1-3) = 1000 x Rating
         level (4-7) = 3000 x Rating
         level (8+)  = 6000 x Rating