Writeup for Crypto Problems in 5spaceCTF 2020

Writeup for 3 crypto challenges in “第五空间” 智能安全大赛 2020 (2020-06-24 09:00 +12h).
- (easy) rosb: RSA common modulus attack
- (medium) UnSafeAES: AES-GCM nonce reuse && forbidden attack
- (interesting) tinysocks: redirect attack on Shadowsocks stream ciphers.

Why Ethereum Has Three Trees

Ethereum has three trees: the state tree, the transaction tree, and the receipt tree. Why do we need three trees? Can we discard one of them? In this post, we explore the principles of the construction of the three trees.

TODO List

Something I want to do.

Writeup for Crypto Problems in HufuCTF 2020

Writeup for 3 crypto challenges in 虎符CTF 2020 (2020-04-19 09:00 +8h).
- (easy) GM: recover every bit of RSA message by using legendre symbol
- (medium) mceliece: break a Mceliece cryptosystem with small parameters
- (easy) pell: solve specified pell equations.