Solutions to the interview CTF tasks¶

Flaggene representerer korrekt svar til oppgavene som benyttes i 2ndre gangs intervjuer.

flag{all_your_base_are_belong_to_us}

Encodings to use :

Ceasar - ROT13 chiper
You get the result: Caesar cipher is indeed the correct cipher in this case. The next cipher was created by Giovan Battista Bellaso almost 500 years ago! For that one you also need a key, which is "cyberlandslaget".

Vigenère cipher
Use the key "cyperlandslaget"
How to solve the task using Cyber Chef (link).
Result text : You found it! The vigenere cipher is very easy to understand and do by hand, but it was very hard to attack without a key. It took nearly 300 years before someone managed to find an attack. So for the next, and last, cipher that is exactly what you are going to do as well. The cipher is still vigenere, but this time the key is 20 characters long and completely random. Good luck!

Vigenère cipher
Key - 20 characters
Key : LOLWTFBBQROFLMAOTTYL
How to find it - use https://www.dcode.fr/vigenere-cipher
Select Knowing the key-length/size, number of letters- enter 20
Hit Auto Decryption
Result text : I hope you found an automatic solver for this, but if you did not, you hopefully learned more than most people who attempted this challenge. The challenge needs a lot of text for attacks to work, so I will ramble on a bit about the flag, if you do not mind. The final flag will consist of the word flag followed by a squiggly open bracket and then, in lower case, the sentence - classic ciphers are easy to break today - with underscores between the words. Finally, the flag will end with a squiggly closing bracket, as to follow the normal flag format.
How to solve the task using Cyber Chef (link).
Answer: - flag{classic_ciphers_are_easy_to_break_today}