Using Blogs to Send Hidden Messages

Well, everyone will say: Isn't that obvious? We can write whatever we want, and click "add comment" or "submit post".

We are talking here about what you can do to send a different message than that in the text you write, other than the information clear in your post.

An example (feel free to add comments for more data carriers):

1. The exact hour:minute of posting your comment.
   
2. Number of posts per day
   
3. Number of letters in each post
   
4. Number of ".", "!", smileys, ... in each post.
   
   This might seem ridiculous, but notice how many statements we end with multiple full stops and the reader will just assume that it is a writing style (a bad one indeed).
   

hour:minute information

You can post the same message but in different times of day, so which minute you choose is an important piece of information:

You can send in any hour:minute out of the 60x60 possibilities. Take the logarithm to the base 2: you have (rounding down) 11 bits (11.813 bits to be exact). That's 2048 different options.

If you posted 3 posts a day (which is not strange for many). Then you have 33 bits, equivalent to 8,589,934,592 different options. Nice !! (I could have written it 'Nice !!!' and you wouldn't think it is strange, but I wanted to send some specific message :) )

I will discuss the rest in separate posts/comments.

Sending Secrets using IM applications (MSN, Yahoo, Skype, ICQ, etc)

Of course, as usual, I am not talking about writing down the secrets in a message and sending it :)

A simple sniffer program can be used to see everything you sent from another machine over the network (your dad can do this for example :) ) Or if you are connected over a wireless link at home or at work, this is clearly easy.

I am thinking more of a normal behavior, that we can make, well, a little bit useful !

Anyone on your list can see your state, right ?

If you are using MSN at work, it is very normal to change your availability every few minutes (your boss is with you in the room, going out for lunch, for a meeting, leaving work and will be unavailable, or off-line, etc). So, this is our media: your online status.

Let's say you are online 10 hours. In MSN, for example, there are 7 states: Online, Busy, Away, ...

You can change the state every 30 mins, and it will not look strange (Just don't make it exactly 30 minutes, 30 +/- 5 minutes). So there are 20 slots in all (10 hrs*2).

How many combinations you can say in a single day: 7 to the power 20 !

That's: 7²⁰ = 79,792,266,297,612,001 (google for this number, you will find many hits ! Weird!).

So, simply, you can send, for example, a credit card, with expiry and code. Or your SSN (of course this might be your boss's SSN that you peeked at, but that will be plain wrong, right?).


Working example:
The credit card number is: 1234-5678-9012-3456

Write it in base 7: = 521020405131521400 (see below on how to do that)

Let's take the following mapping: Online = 6, Busy = 5, Be right back = 4, Away = 3, On the phone = 2, Out for Lunch = 1, Offline = 0

Therefore, in the first 30 minutes: "Busy", next 30 minutes "On the phone", then "Lunch", then "offline", then "Phone", ... got it?

Your friend at home, or whatever, will write down every state he sees, all day, then he has the list of numbers (in base 7), he will convert it back to decimal, and voila, here is the secret transferred :)

Base Conversion:
Changing things from base to base is easy (specially if they are binary, hexadecimal, or of course decimal: Windows calculator can do it for you). But for our case, 7 is a little boring, and it will need the calculator beside you, and you will do it in a minute.

I am not sure if anyone wants to see how to do the conversion, if so, tell me and I will post it in another post here.

Brief example: convert 123 from decimal to base 7:

123 divided by 7 = 17 remainder 4 (then 4 is the first number on the right)
17 divided by 7 = 2 remainder 3
2 divided by 7 = 0 remainder 2
Then the result is 234

Converting it back:
2*7^2 + 3*7^1 + 4*7^0 = 123 (easy...)


Enjoy Instant Messaging :)