Find the source code to all the challenges over here https://github.com/DaKeiser/zensectf You can also deploy it locally, and run all the challenges.(Due to some issues, we shall share the code, once we shut down our contest server.) Steps to deploy git clone https://github.com/DaKeiser/zensectf.git cd zensectf ./rebuild.sh ./redeploy.sh

Crypto Cryptography is the form of communicating with someone in the presence of a third party and making sure that no one other than the reciever can understand the message sent. You can encrypt your data using many ciphers, like Caesar cipher(which is basically making A=N, B=O ... Z=M ie. Rotation by 13 characters), or any rotation by x values called ROT x cipher. There are more advanced ciphers like Vigenre Cipher etc. But the major issue with these ciphers are that they can mostly be decrypted using entropy analysis. There are many tools online which could help you decode them too. So using Key based encryption is a better alternative compared to these. A method used to encrypt data is by using One Time Pad. This is cryptographically the strongest way to encrypt a message. But it comes with its own set of issues. You cannot reuse the pad Transfer of pad to the reciever to decrypt the message is an issue.

Hello all Hope you all are doing fine. This is a message from the CTF Wing of Zense. We have got a very large summer break this year, and we must try to take this opportunity to explore different domains, be it Competitive Programming, Development, Machine Learning etc. And we would like to take this opportunity to introduce you to CTF. Unlike CP, ML and development, most of you might not have heard of CTFs, but that is fine. Even we didn't know until recently. But trust me there is huge competition among various teams out there. And now is the perfect time to explore. You never know where you might find your interests. So what is a CTF? A CTF aka. Capture the Flag is a contest where there is a territory that has to be infiltrated and objects that need to be captured while fighting against the opposition or competition of another team. You might have heard it in video games frequently. The rules are similar here too. You have a set of challenges and you must find out the vulnerability and exploit it to find a flag. Now you know why it is known as Capture the Flag. So what is a flag? A flag is something which is proof that you have solved the challenge. In our case it is a phrase that usually looks like flag{...} Why do you need to CTF?