Correct again Ace, I see your plan, solve them while everyone else is sleeping.
Since Ace was kind enough not to give an explanation, here is how it's worked out for those interested in cryptography.
The model I used is called Caesar Box Cipher (named after it's first user, Julius Caesar), it works by using square numbers. Any message where the total characters equal a square number, in this case 16, can be encoded with the Caesar Box. Let's work in reverse to decode this message. First, you take the total number of letters and divide it into groups, each group containing the square root of the total number of letters. So in this case, 4.
T A S A H K N L E E O I C I T E
Becomes;
T A S A | H K N L | E E O I | C I T E
Still doesn't make much sense at all right? Now we arrange those groups into a perfect box shape, hence why only square numbers will work. Then, you read the message in columns rather than rows, starting from the top left corner.
T A S A
H K N L
E E O I
C I T E
Clever, isn't it?