diffie-hellman Description Alice and Bob wanted to exchange information secretly. The two of them agreed to use the Diffie-Hellman key exchange algorithm, using p = 13 and g = 5. They both chose numbers secretly where Alice chose 7 and Bob chose 3. Then, Alice sent Bob some encoded text (with both letters and digits) using the generated key as
morse-code Description Morse code is well known. Can you decrypt this? Download the file here. Wrap your answer with picoCTF{}, put underscores in place of pauses, and use all lowercase. Solving The soundfile is a morse code You could either translate it by your self with the morse alphabet or use this link Change all characters to lowercase and replace
credstuff Description We found a leak of a blackmarket website’s login credentials. Can you find the password of the user cultiris and successfully decrypt it? Download the leak here. The first user in usernames.txt corresponds to the first password in passwords.txt. The second user corresponds to the second password, and so on. Solving We got a tar file – extract
basic-mod2 Description A new modular challenge! Download the message here. Take each number mod 41 and find the modular inverse for the result. Then map to the following character set: 1-26 are the alphabet, 27-36 are the decimal digits, and 37 is an underscore. Wrap your decrypted message in the picoCTF flag format (i.e. picoCTF{decrypted_message}) Solving This challenge is similar
basic-mod1 Description We found this weird message being passed around on the servers, we think we have a working decrpytion scheme. Download the message here. Take each number mod 37 and map it to the following character set: 0-25 is the alphabet (uppercase), 26-35 are the decimal digits, and 36 is an underscore. Wrap your decrypted message in the picoCTF
AAAAA AAAAA. That’s all Download AAAAA Okay – first of all, like always I run file on this AAAAA file. This will tell us, that this is a data file. After that, I tried binwalk. BÄM There is an image included. My colleague uses CyberChef for this. There you can import the file and run Extract files on. I just
DISCORD SHENANIGANS We considered giving you a free flag. However, we decided against it. In general, we would never do that! Or would we? That’s the beginning of a good CTF! Discord is the new Twitter. To be able to solve this challenge, you’ll need to join our discord. Link in the Rules page. Todos The flag is hidden in
Noise Messi: ‚When the year starts, the objective is to win with all the team, personal records are secondary‘ Todos Given was this picture: In this stego challenges the first approach is to check the file type and look for some strings. $ ~ # file challenge.png challenge.png: PNG image data, 926 x 1262, 8-bit grayscale, non-interlaced That looks normal…
Friends Bielsa: ‚Everything is allowed, except stop fighting‘ Given was this image: Todos Like always – I check strings and exiftools and the file itself! But no command give us something. $ ~ # file messi.jpg messi.jpg: JPEG image data, JFIF standard 1.01, aspect ratio, density 1×1, segment length 16, baseline, precision 8, 720×628, components 3 exiftool messi.jpg > messi.jpg_exifdata
3in1 Description Like Nescafeeeee! Attachments https://ctf.k3rn3l4rmy.com/kernelctf-distribution-challs/nescafeee/AES.py Todos To decrypt the string in the given AES.py script (String is in scriptfile as a comment). from Crypto.Cipher import AES from Crypto.Hash import SHA256 f = open('progress.txt', 'r') password = ("abda") hash_obj = SHA256.new(password.encode('utf-8')) hkey = hash_obj.digest() def encrypt(info): msg = info BLOCK_SIZE = 16 PAD = "{" padding = lambda s: s