security system

recently i have an idea in my mind,and want to make some thing of it.

to design a system which works as,

i through same special ink write anything on page or first page of any book.

then when that page is passed through a censor type thing it will detect it and rings any alarm.

what the key is when any page which do not have that special ink when passed through system wonnt cause alarm to ring.


if let say i made such project and want to modify this project in a way that project keeps record of the time and date when alarm rings through interfacing.


but the problem is so far what i write is just a thinking and i don't know from where to start and most important how to start,how to write on paper,and from which ink i write etc.

so i think in this forum many of electronic genius are present and i hope any one of those might give me some useful way to start.

remeber i wish to use microcontroller for this.

i am waiting for reply.

tc
bye

The simplest cheapeset and easiest to implement method I can think of is simply using a UV or maybe an IR ink in a small portion of the page, it's easy to scan using only an extra LED diode in a common scanner and modern scanners are good enough that a time code and other information could easily be encoded in a very small place. Virtually any method used though is going to be relativly easy for someone to counterfeit. The U.S tresury has a tough enough time at it. You could use highly encrypted keys on the paper instead of simple verification codes but that would be very difficult to manage on a system wide basis.
Your post is missing the most common piece of information people fail to mention.
What are you trying to do EXACTLY?

You could print virtually fool proof one time use authentication codes on individual documents but it would be useless for general mass document verification.

thankx.

now what i exactly want is to build a security system may be use in jail or anywhere else,
what it really do is that i use um ink to write sumthing anywhere on paga or if in jail then on the cloths ,and when they pass through any gate sensor detect it an rings an alarm.

hope u have understand this.
remeber i use to build microcontroller for this and IR alsoo.

if u plz explain this and have any source of it from where i can get theory of such thing ill be greatful to u..

ttc

bye