You are extremely lucky!
Today we open the first Crypto-shop in Gravity falls http://10.0.192.235:61741/index.php/ and we even made up crypto-currency – gravitycoins!
I invite you to take pat in beta-testing. All we have for now is a file…
Continue reading [Juniors CTF 2016] [Web 500 – Crypto-shop] Write Up
Recover the private key and the flag.
Hints: Check your padding 🙂
Continue reading [EKOPARTY PRE-CTF 2015] [Cry100 – RSA 2070] Write Up
Session Start: Thu Feb 05 20:49:04 2015
Session Ident: #mastercsi
[20:49] * Now talking in #mastercsi
[20:49] * Topic is 'http://mastercsi.labri.fr/'
[20:49] * Set by admin!~admin on Sat Nov 22 00:06:50
[20:49] and I got an old RSA key that Alice used
[20:49] alice, alice's? you gotta be kidding me?
[20:49] haha no
[20:49] but there was just half, I had to complete with random values to make it work
[20:49] it seems to work anyway, if you have something to decipher...
[20:49] wait, I have her public key lying around somewhere, and even an encrypted file. I've always wondered what it was ...
[20:49] maybe it's the same key?
[20:50] I sent you the thing, take a look
[21:22] * Disconnected
Session Close: Thu Feb 05 21:22:11 2015
The validation key is the message encrypted with the private key of Alice, rebuild it using the following files:
mykey.pem (If you have some issues trying to download this file : right click -> save as …)
Continue reading [HackingWeek 2015] [Crypto4] Write Up
Bob uses a RSA public key with the public exponent e = 65537 and modulus:
N = 55089599753625499150129246679078411260946554356961748980861372828434789664694269460953507615455541204658984798121874916511031276020889949113155608279765385693784204971246654484161179832345357692487854383961212865469152326807704510472371156179457167612793412416133943976901478047318514990960333355366785001217
The challenge validation key is given by the md5sum of the value of its private key d.
Continue reading [HackingWeek 2015] [Crypto2] Write Up