“Great Job You Got It”
This type of code is known as a Caesar Box (Julius Caesar was the first to write codes this way.) To decipher the message, simply divide the code into four groups of four (you can also divide them into groups such as 5 groups of 5 or 6 groups of 6 depending on the number of letters in the phrase), and rearrange them vertically like this…
G T Y O
R J O T
E O U I
A B G T
Then you read vertically, column by column.
Source…