From: bobkatz@panix.com (Bob Katz)

Subject: Photoshop Serial Number Algorithm

Date: 4 Oct 1994 16:14:03 -0400

[ Article crossposted from comp.sys.mac.programmer,comp.sys.mac.system,comp.sys.mac.apps ]
[ Author was Jens Alfke ]
[ Posted on Fri, 30 Sep 1994 21:09:13 GMT ]

Bob Zigon, bobz@truevision.com writes:
>    Photoshop (as well as several other programs) has this funky serial
> number mechanism
> on the front end when you install them. They ask you for a serial number
> and are able to
> tell you if it is valid. Our assumption is that the instance you are
> running knows nothing of the serial number you are typing in.

Actually it does. Photoshop uses an undocumented feature of the Power Manager
to send the serial number as a series of modulated pulses out through the
power supply into the AC line, which are picked up at the power station and
routed to Adobe (yeah, the power companies are trying to get into the
Infobahn stuff too, just like the phone and cable companies.) Adobe then
looks up the serial number and sends a pulse back if it's valid. The
bandwidth on this stuff isn't great, but you can guarantee that every Mac is
plugged into the network!

I think there is a technote that describes the API to this; the hardware
folks were having trouble getting that feature to work with European 50Hz
power lines so they decided not to document it initially, but then the DTS
people released the info anyway.

--Jens Alfke                           jens_alfke@powertalk.apple.com
                   "A man, a plan, a yam, a can of Spam ... Bananama!"
-- 
Bob Katz   Voice: (212)369-2932     | "There are two kinds of fools,
Pres. & Chief Eng. DIGITAL DOMAIN   | One says--this is old and therefore good.
Audiophile recording, CD Mastering, | The other says--this is new and therefore
manufacturing, consulting.          | better."