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CTF writeups Heap Exploitation

DEFCON 2018 Quals: It’s a me, Mario

Although I didn’t have much time to do CTFs as of late, I sat down for part of the DEFCON 2018 Qualifiers with HATS_SG. Among the challenges solved, Mario was a rather peculiar (and somewhat amusing) one that involved multiple heap exploitation techniques along with some tricks to get an exploit working successfully. Overview We […]

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Cryptography CTF writeups

PlaidCTF 2015 – Crypto/Parlor2

After going bankrupt last year, the folks behind parlor from last year have decided to set up a new betting service! PlaidCTF 2015 – Crypto/Parlor2 We were given a gambling application where we could choose some modulus . This modulus would be used by the server to compute a random number , which we have […]

Categories
Cryptography CTF writeups

PlaidCTF 2015 – Crypto/Lazy

My knapsack brings all the boys to the yard, and they’re like “that crypto is hard” (note: this flag is not in the flag{} format) PlaidCTF 2015 – Crypto/Lazy The challenge provided a few files: pubkey.txt, ciphertext.txt, knapsack.py, utils.py. After inspecting the code, it seems that the contents of ciphertext.txt was encrypted using Merkle-Hallman knapsack (MHK) cryptography, […]