Rating: 5.0

**In this challenge we are given a txt file with this description:**
**“We were following a suspect in hot pursuit when he suddenly disappeared. We were left standing in front of a mysterious lab. We didn’t find much, except for a small sheet of paper with this message printed on it. Can you help us decipher it?”**
![](https://i.imgur.com/XZCUeRW.png)

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**Pretty fast we can see the first part of the flag becomes GTTAAATTCGGT**

![](https://i.imgur.com/LxEE605.png)

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**If we do a quick search of “GTT AAA GTT TTC GGT” and go to images we find a bunch of results talking about DNA**
![](https://i.imgur.com/yvKcMmJ.png)

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**After that we searched for “Dna crypt algorithms” and we find the first article**

**If we open the table and compare these with the first letters we got we see that they indeed match up**
![](https://i.imgur.com/ePN3V4k.png)

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**Decoding each character with the table gives us the flag “CYCTF{S0LV1NG_PR08L3M5_1S_1N_Y0UR_DNA}”**

Original writeup (https://joren.tk/2020/11/02/gattaca/).