> [name=Curious]

## Train Of Thought & Solution
After downloading, it turned out to be a zip file. Let's try extracting it first


It can be noticed that although there was an error reported by `unzip`, a file named `chemistry.png` was still extracted from the archive.

> My original intention was to create a pseudo-encrypted zip file, but it seems that `unzip` is a bit clever and directly extracted it QQ

If you try to open `chemistry.png` directly, you will find that it cannot be opened. Let's use the `file` to examine the file


You will find that when using the `file` command, this file is identified as an ELF file. Let's use `xxd` to examine the file.


It appears that the original PNG's magic number has been changed to that of an ELF file. Let's change the magic number back to `8950 4e47 0d0a 1a0a`


> Here, you can use `vim chemistry.png` to open the file, then enter `:%! xxd` to directly modify the hexadecimal content. After making the changes, enter `:%! xxd -r` to return to normal editing mode. Finally, save the file and exit

After opening the image, you can see a compound that you're unsure about. You can use Google's reverse image search feature to find more information about it.



After visually comparing, it appears that the compound is Leucine. Following the format of the flag `LoTuX{[A-Z][a-z]*}`, you can fill in the English name of Leucine with the first letter capitalized and the rest in lowercase to obtain the correct flag.

{%hackmd M1bgOPoiQbmM0JRHWaYA1g %}