RTCP - Hump's Day

Posted on sam. 25 janvier 2020 in CTF

solves : 38

Point : 1050

Happy Hump's Day
Happy TGIF!
Happy Saturday
Happy Tuesday +1
Happy Thursday +1
Happy TGIF -2
Happy Monday!
Happy Hump's day +5 3 times
Happy Saturday +3
Happy TGIF +1
Happy Tuesday +0
Happy Friday +3
Happy TGIF -1
Happy Wednesday
Happy TGIF
Happy Sunday
Happy Saturday -5

Hint: Hump's day is on what day of this ctf?
Hint 2: The Lotus would be proud. Decimate your enemies, gather more hexenon, string the grineer up! simple. Isn't it?

The hint gives us the correspondence for the Hump's Day: Wednesday.

We can use the number of the day in the month (22) or the week relative number (3, as Sunday is 0).

The second hint gives some instructions about it: Decimate, hexenon (looks like hexa) and string.

So, we have to get digit between 0 and 9. The month number is too hight.

When we put together all the number, we got: 3563531888962843501.

We can convert it as a hexa string and decode the result (the sed adds the flag part):

$ printf '%x' 3563531888962843501 | xxd -r -p | sed -E 's/^(.*)/rtcp{\1}/'
rtcp{1t5_ch3m}