The flag is encrypted by this code, can you decrypt it? crosscheck.tar.xz Summary: breaking RSA modulos with related primes.
Tag: crypto
May 04
VolgaCTF Quals 2015 – CPKC (Crypto 400) writeup
cpkc A home-brewed cryptosystem, should be easy to break. Its keyspace seems to be rather large though… challenge.tar Summary: LLL-based attack on NTRUEncrypt-like cryptosystem.
Apr 19
PlaidCTF 2014 parlor writeup
The Plague is running a betting service to build up funds for his massive empire. Can you figure out a way to beat the house? The service is running at 54.197.195.247:4321.
Apr 17
PlaidCTF 2014 RSA writeup
Our archaeologists recovered a dusty and corrupted old hard drive used by The Plague in his trips into the past. It contains a private key, but this has long since been lost to bitrot. Can you recover the full key from the little information we have recovered?
Mar 02
Boston Key Party CTF – Differential Power (Crypto 400)
we hooked up a power meter to this encryption box. we don’t know the key. that’s what we want to know. you can encrypt any string of 8 characters on the service http://54.218.22.41:6969/string_to_encrypt encrypt.asm chall source (released after ctf)
Feb 09
Olympic CTF 2014 GuessGame (300)
Be careful, it’s cheating! nc 109.233.61.11 3126 Summary: discrete logarithm with group oracle
Feb 02
Olympic CTF Sochi 2014 Registration is Open
Let there be Olympics MSLC proudly presents…Alright, do we even need words here? Game starts: February 7th, 2014 16:14 UTC (yeah yeah, those Sochi number freaks… it’s 20:14 in MSK timezone) Game ends: February 9th, 2014 16:14 UTC Sign up: https://olympic-ctf.ru/ Prize set: 1500 USD, 1000 USD, 500 USD. Expect decent tasks. Twenty of them.
Jan 07
Sudden CTF syndrome
Happy new 2014 and merry Orthodox Christmas if you’re religious ;-D Maybe you already know hack you and hack you too, so I won’t even say that hack you is an individual CTF that we originally held for our university freshmen and opened it for everyone interested in the world. Couple days after this New …
Jun 17
Defcon CTF Quals 2013 – All Web Challenges (3dub)
Summary: 3dub (1) – babysfirst: SQLite SQL injection 3dub (2) – badmedicine: Stream cipher bit flipping 3dub (3) – hypeman: Rack/Sinatra session secret disclosure 3dub (4) – rememberme: Bruteforce 3dub (5) – worsemedicine: Block cipher bit flipping
Jun 02
PHD CTF 2013 Hackskell (500)
We’ve got a screenshot of some encryption, here’s the text transcribed. Please say what’s there. Summary: a couple of modular equations
Jun 02
PHD CTF 2013 from hell import crypto (100)
Decrypt the message: 7y9rr177sluqv1r4pw Hint: $ at
Jun 02
PHD CTF 2013 ReStART (400)
We heard hellman encrypted the flag using his super secure keygen. Break it! Summary: RSA with the lower half of the secret exponent bits leaked.
Apr 22
PlaidCTF 2013 Blech (Crypto 200)
You get arbitrary code execution…. as long as it’s code we approve of. Source available at blech.py Service running on 54.234.73.81 port 1234 blech.py Summary: RSA cube root attack
