Crypto Challenge For Begineers

 

 

This is challenge is come from csaw ctf challenges

okay its using encrypted pre-shared key but, i don't know what is the key is..?

after downloading the png .I check the file format

 Next i check the Binwalk to extract any binary data

Binwalk:

Binwalk is an open source firmware extraction tool that extracts embedded file systems from firmware images. Created in 2010 by ReFirm Lab's own Principal Reverse Engineer Craig Heffner, Binwalk is widely recognized as the leading tool for reverse engineering firmware images.

 it has the ordinary compressed file .

Nothing to get ordinary steps so, i want to try stegsolver ,

"Stegsolve is an immensly useful program for many steganography challenges, allowing you to go through dozens of color filters to try to uncover hidden text" most of the time stegsolver is helpful , and i change the file simultaneously i get the output like this

 

 

something is present on the png ,the stegsolver output is

stegsolver has another options,is called analyse using image combiner, it take two image input so i try this and its works i got the flag..!

its use two image to do xor and ,then I xor two image I got flag the format of base64 encode.

ZmxhZ3swbjNfdDFtM19QQGQhfQ== 

The flag is : flag{0n3_t1m3_P@d!}