Character Encoding

We are given these characters:

43 54 46 6C 65 61 72 6E 7B 34 35 43 31 31 5F 31 35 5F 55 35 33 46 55 4C 7D  

Since they are numbers and letters between A and F, they seem to be ASCII characters in hexadecimal representation.

For instance, 0x43 is the code for C, 0x54 for T and 0x46 for F.

To decode all the characters, we can use the following “one-liner”:

$ xxd -r -p <<< '43 54 46 6C 65 61 72 6E 7B 34 35 43 31 31 5F 31 35 5F 55 35 33 46 55 4C 7D'  
CTFlearn{45C11_15_U53FUL}