# Walkthrough There is one sound file in the zip which is some dial tones. If you search up these tones they are called “DTMF Tones” which are standardize. There are many ways to convert them to the numbers but I used my phone and an app called “DTMF Decoder”. From here you will get the numbers pressed out on the keypad with pauses in between. ``` 23 31 43 47 83 71 19 23 43 17 67 37 23 31 11 7 71 41 13 ``` If you look at these numbers they have a mathematical property to them, they are all primes. So then you get a prime list and find out what order prime they are. ``` 9 11 14 15 23 20 8 9 14 7 19 12 9 11 5 4 20 13 6 ``` From here they are low numbers. Here we can simply substitute the alphabet in for each number. (For example 1 = A, 2 = B, 3 = C, etc...) It will say: ``` I K N O W T H I N G S L I K E D T M F ``` And that is then end of the HTB Challenge!