21 docs tagged with "crypto"

I love this cryptosystem so much, I carry it everywhere in my backpack. To lighten the load, I make sure I don't pack anything with high densities.

I tried to send you an important message with RSA, however I messed up my RSA implementation really badly. Can you still recover the flag?

Here's my secure search engine, which will only search for hosts it has in its trusted certificate cache.

I overheard my professor talking about ellipse curve cryptography. I tried googling it, but didn't find anything so I implemented it myself.

Solution

In a post-apocalyptic world, you are an aspiring botanist who has dedicated his life to the study of plants and their genetic manipulation, and is an expert on their embryonic stage. On your journey around the world, hoping to find a way to artificially create plants that can withstand Earth's cruel environment, you have come across a new species in a seemingly inhospitable area. You know it's time for you to unlock the secrets of nature. Will 5 plants be enough?

Now you've got the hang of the various encodings you'll be encountering, let's have a look at automating it.

As we've seen, lattices contain hard problems which can form trapdoor functions for cryptosystems. We also find that in cryptanalysis, lattices can break cryptographic protocols which seem at first to be unrelated to lattices.

The Bank of the World is under attack. Hackers found a way in and locked the admins out. However, the netcat authentication by the intruders is not perfectly secure. Could you help the admins log in?

I won't have have to worry about running out of entropy, I'm going to have my OTP generated forever with this new script!

I've hidden two cool images by XOR with the same secret key so you can't see them!

I encrypted a secret message with RSA but I lost the modulus. Can you help me recover it?

I've learnt that when life gives you lemons, if you look at things the right way they taste just like pairs.

This is my secure timestamp signing server. Only if you can produce a signature for "unlock" can you learn more.

Another day of flexing your muscles in the mirror and still not being satisfied with your body image. Pumped full of adrenaline and creatine, the only thing missing for you is a good workout program. We heard that the best one out there is from the Swole Eagle gym, but they've closed down the registrations because the FDA is hunting them down for the one secret that natty bodybuilders hate. With an appetite for breaking rules, and an oven full of protein cookies ready to become the post-workout treat of the day, you'll have to get the right exercise going to not waste any of that precious muscle mass building potential. Infiltrate the portal of the gym membership and get the exercise program you know you deserve! 🍪

I heard Shor's algorithm can do all sorts of nasty things to RSA, so I've decided to be super modern and protect my flag with cool new maffs!

Are you ready to win lottery? Guess the Random Lotto Numbers. It's TIME you become a millionaire.

I think this is safe... Right?

To be accepted into the upper class of the Berford Empire, you had to attend the annual Cha-Cha Ball at the High Court. Little did you know that among the many aristocrats invited, you would find a burned enemy spy. Your goal quickly became to capture him, which you succeeded in doing after putting something in his drink. Many hours passed in your agency's interrogation room, and you eventually learned important information about the enemy agency's secret communications. Can you use what you learned to decrypt the rest of the messages?

When you connect to a website over HTTPS, the first TLS message sent by the server is the ServerHello containing the server TLS certificate. Your browser verifies that the TLS certificate is valid, and if not, will terminate the TLS handshake. Verification includes ensuring that:

Who needs AES when you have XOR?