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rishitsaiya
53fd30619d
|
4 years ago | |
|---|---|---|
| .. | ||
| Flag.png | 4 years ago | |
| Gandalf.jpg | 4 years ago | |
| README.md | 4 years ago | |
| String1.png | 4 years ago | |
| String2.png | 4 years ago | |
| String3.png | 4 years ago | |
README.md
GandalfTheWise
The main idea finding the flag is XOR strings.
Step-1:
After downloading Gandalf.jpg, I tried strings Gandalf.jpg and got this output. These are initial strings embedded in Meta data of image.
JFIF
+Q1RGbGVhcm57eG9yX2lzX3lvdXJfZnJpZW5kfQo=
+xD6kfO2UrE5SnLQ6WgESK4kvD/Y/rDJPXNU45k/p
+h2riEIj13iAp29VUPmB+TadtZppdw3AuO7JRiDyU
...
Step-2:
I decrypted the 1st Base64 encrypted string i.e. Q1RGbGVhcm57eG9yX2lzX3lvdXJfZnJpZW5kfQo= at https://cryptii.com/.
It gives a false flag CTFlearn{xor_is_your_friend}, but on a brighter side it gives idea of XOR'ing the next 2 strings.
Step-3:
So, I decrypted remaining 2 strings to get hexadecimal texts because in that RFC, ASCII text isn't possible.
Step-4:
I XOR them online at: http://xor.pw/ to get the flag.
Step-5:
Finally the flag becomes:
CTFlearn{Gandalf.BilboBaggins}