Cryptography

Mod 26 [10 pts]

Description

Cryptography can be easy, do you know what ROT13 is? cvpbPGS{arkg_gvzr_V'yy_gel_2_ebhaqf_bs_ebg13_Ncualgvd}

Solution

The description gives it away. I used CyberChef to solve.

Flag: picoCTF{next_time_I'll_try_2_rounds_of_rot13_Aphnytiq}

Mind your Ps and Qs [20 pts] [Not Solved]

Description

In RSA, a small e value can be problematic, but what about N? Can you decrypt this? values

Solution

a

Flag:

Easy Peasy [40 pts] [Not Solved]

Description

A one-time pad is unbreakable, but can you manage to recover the flag? (Wrap with picoCTF{}) nc mercury.picoctf.net 36449 otp.py

Solution

a

Flag:

New Caesar [60 pts] [Not Solved]

Description

We found a brand new type of encryption, can you break the secret code? (Wrap with picoCTF{}) mlnklfnknljflfjljnjijjmmjkmljnjhmhjgjnjjjmmkjjmijhmkjhjpmkmkmljkjijnjpmhmjjgjj new_caesar.py

Solution

a

Flag:

Mini RSA [70 pts] [Not Solved]

Description

What happens if you have a small exponent? There is a twist though, we padded the plaintext so that (M ** e) is just barely larger than N. Let's decrypt this: ciphertext

Solution

a

Flag:

Dachshund Attacks [80 pts] [Not Solved]

Description

What if d is too small? Connect with nc mercury.picoctf.net 41508.

Solution

a

Flag:

No Padding, No Problem [90 pts] [Not Solved]

Description

Oracles can be your best friend, they will decrypt anything, except the flag's ciphertext. How will you break it? Connect with nc mercury.picoctf.net 33780.

Solution

a

Flag:

Pixelated [100 pts] [Not Solved]

Description

I have these 2 images, can you make a flag out of them? scrambled1.png scrambled2.png

Solution

a

Flag:

Play Nice [110 pts] [Not Solved]

Description

Not all ancient ciphers were so bad... The flag is not in standard format. nc mercury.picoctf.net 33686 playfair.py

Solution

a

Flag:

Double DES [120 pts] [Not Solved]

Description

I wanted an encryption service that's more secure than regular DES, but not as slow as 3DES... The flag is not in standard format. nc mercury.picoctf.net 3620 ddes.py

Solution

a

Flag:

Compress and Attack [130 pts] [Not Solved]

Description

Your goal is to find the flag. compress_and_attack.py nc mercury.picoctf.net 57393

Solution

a

Flag:

Scrambled: RSA [140 pts] [Not Solved]

Description

Hmmm I wonder if you have learned your lesson... Let's see if you understand RSA and how the encryption works. Connect with nc mercury.picoctf.net 50075

Solution

a

Flag:

It's Not My Fault 1 [300 pts] [Not Solved]

Description

What do you mean RSA with CRT has an attack that's not a fault attack? Connect with nc mercury.picoctf.net 56093. not_my_fault.py

Solution

a

Flag:

New Vignere [300 pts] [Not Solved]

Description

Another slight twist on a classic, see if you can recover the flag. (Wrap with picoCTF{}) eljodmjdjcnfcdmgbleojbgngojkkdpimebgeigpdkjpmgngpfpgelemjoglghjd new_vignere.py

Solution

a

Flag:

Clouds [500 pts] [Not Solved]

Description

Cloud watching is a lot of fun! There are so many different shapes you see in them, and so many different types. They even inspired me to dig up an old cipher I once found to store notes about them. See if you can decrypt them! nc mercury.picoctf.net 20974 clouds.py The flag for this challenge does not include the standard picoCTF{} wrapper.

Solution

a

Flag: