> For the complete documentation index, see [llms.txt](https://rayyanwong.gitbook.io/rayyan/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://rayyanwong.gitbook.io/rayyan/ctfs/lag-n-crash-2022-march/lnc2022-writeups/fone-forensics.md).

# Fone ( Forensics )

Challenge: Fone ( contributed by yueming )

I used an online spectrum analyzer to check if there was a hidden word or image. However what i got was a bunch of bars with two lines in them. The name of the challenge was Fone and the audio sounded like a phone so I thought Dual tone multi frequency might be useful. I compared the higher and lower frequency for each bar and compared it to the DTMF table to get which key was being input.

![](https://lh5.googleusercontent.com/lU_jkLgmjmDG6x_gQ6KX3wS8Tdwokbikmk-EqB1L1aMLgfSRM8vxfFb-aBiFUE-5dnUvLmm-Mcb6Mzuxg3T3vvcjWz6tSTO4Jy8pQKXel2GgJEiVrGqz1tMHoIYRQl4RU_zeEgKA)

<mark style="color:blue;">**`LNC2022{763*132ABD32C190##256791A}`**</mark>