Personal site · London
I’m a crypto enthusiast, a long-term Bitcoin holder and I was passionate about smart contracts, Solidity auditing and competitive programming. I build and share what I learn along the way. I’m currently creating videos and sharing ideas on Twitter and YouTube.
Donations on Solana (SOL, USDC, or USDT): 6rpLveaLdWLouBtE1KaenDQvrQQmK65rFM8u7uRxNSZT
I enjoy smart contracts and Solidity auditing. You can find my work on Code4rena and Sherlock.
For code and ongoing notes, visit GitHub and my progress reports.
I also share smart-contract lectures on Bilibili.
I love competitive programming. Here are my profiles and archives:
Beijing University of Posts and Telecommunications
Bachelor’s in Computer Science · 2011–2015
Master’s in Information Security · 2015–2018
While at university, I maintained a monthly life summary on CSDN and a Chinese writing archive here.
Those posts are older, but they remain part of the record.
Notes on engineering, security, algorithms, and life.
到了一定年纪，你发现你越来越不喜欢装了。也是越来越不能装了，也是装不下去了。
记录我十几岁时候的几个印象最深的片段，这几天在梦里悉数出现。
Puzzle 2 is very similar to Puzzle 1, with the only difference being that this time we need to understand the CALLVALUE opcode.
I recently discovered that the EVM Puzzle series is an excellent set of challenges to test our understanding of EVM opcodes. The puzzles can be found at this link: https://github.com/fvictorio/evm-puzzles. In this blog post, we will focus on solving the first puzzle.
The gist of this question is that the “Recovery” contract created a “SimpleToken” contract but lost the address of the SimpleToken contract. Now, the goal is to find the address of the SimpleToken contract and transfer the ETH inside it.
This question has a difficulty rating of 4 stars and is a very interesting one.
In ERC20, there is not only transfer function, but also transferfrom function.
In this question, even if the transfer function is overridden and there is a lockTokens modifier to prevent transfers, the transferFrom function in ERC20 is not overridden. We can utilize this function to perform transfers.
This question requires calculating an XOR value. To get the XOR value, we need to perform XOR operation again. The way the XOR value was originally calculated in the problem statement is the same logic that needs to be implemented in our smart contract code to get the XOR value.
This question is actually straightforward. It is similar to the previous one, but this time it requires brute force and understanding the value logic of unit32, uint64, uint160