Easy Peasy 2017 CTF | RC3 Writeup
We were given an image filled with emojis. Also there was a clear division between a first paragraph and a second one.
The first paragraph didn't have any repeated emojis, and they were also aligned in order of appearance as in the smartphone's emoji keyboard.
The second paragraph did have repeated emojis and wasn't ordered.
This made me think that the first paragraph was a reference that was used to compare an alphanumeric character set to the second paragraph, which was the actual flag (or one could assume).
So with all the possibilities that modern technologies offer to edit and image, I opened Paint and gave each emoji in the first paragraph.
So with everything set, the second paragraph turned out to be a base64 encoded string (as one of my teammates noted as per the two final aubergines).
The first paragraph didn't have any repeated emojis, and they were also aligned in order of appearance as in the smartphone's emoji keyboard.
The second paragraph did have repeated emojis and wasn't ordered.
This made me think that the first paragraph was a reference that was used to compare an alphanumeric character set to the second paragraph, which was the actual flag (or one could assume).
So with all the possibilities that modern technologies offer to edit and image, I opened Paint and gave each emoji in the first paragraph.
VGhpcyBpcyB0aGUgbWVzc2FnZQ==
And decoded:
This is the message
So the flag was RC3{This is the message}.
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