Blog entries with tag “Computer science

A note on (non-)uniform reductions

I learnt how to write uniform hybrid reductions in my rudimentary cryptography course, which are beasty beauties that wrap an adversary, trying break each of the many underlying cryptographic assumptions simultaneously. However, those constructions are less easy to write and read than using the transitivity of computational indistinguishability up to polynomially many times. The latter involves writing out the (perhaps polynomially many) hybrids and arguing that adjacent hybrids are indistinguishable. I also learnt non-uniform reductions, noticeably the technique to only work with deterministic adversaries. I’m writing a proof using hybrid argument lately, and I asked my advisor about whether I should write the beast or just the hybrids…

A note on (non-)uniform reductions

The Code Book (Simon Singh) 读书笔记

操作系统课中讲安全的一节是代课老师上的,期间他推荐了 The Code Book (Simon Singh) 这本书,说是讲密码学历史的。我对密码学感兴趣,就读了一读,并照“不动笔墨不读书”的原则,记了读书笔记,发表出来以飨观众。

The Code Book (Simon Singh) 读书笔记

如何在操统课 Bitcoin 大作业组间比赛歇菜

交叉信息研究院的本科生操作系统课程的大作业很奇特,并不是 4 个 NachOS 作业,而是两次 NachOS、两次分布式数据库。最后一次大作业是要写一个 Bitcoin 挖矿程序,而且还有组间比赛,各个小组的矿机和客户端会一起运行一段时间,最终获得最高手续费的矿机会获胜。

如何在操统课 Bitcoin 大作业组间比赛歇菜

Is the pattern you found persuasive?

Starting from the classic puzzles of finding patterns in a sequence, this entry explores the framework to define persuasive patterns. The framework is found to be quite self-contained in the sense that it is ‘asymptotically invariant’ to the choice of ‘language of expression’. The only short-coming of this framework is that it works only for computable sequences, yet the process of pattern discovery is incomputable.

Is the pattern you found persuasive?

Discount aux Galeries Lafayette and NP-completeness

I allowed myself some CHANEL products to ‘reward’ myself for the acceptance of my first cryptography paper. I also consider spending money at its best value an interesting game. A commonly-seen discount aux Galeries Lafayette Xidan (Beijing) leads to an obviously NP-complete problem. Haha!

Discount aux Galeries Lafayette and NP-completeness

Of Kerckhoffs’ principle

Let me explain the classic idea that ‘the algorithm of a crypto system should be considered and made public’ to you. Particularly, I will discuss what it means by ‘crypto system’, which tells us what information should be no secret at all.

Interviewed by THU IIIS

I was participating Advanced Assessment for Admission (AAA) of Tsinghua Union, passed the first phase and was interviewed by Insititute for Interdisciplinary Information Sciences of Tsinghua University. Here is a transcript of the interview.

Interviewed by THU IIIS

去 THU IIIS 面试

我参加了“华约”(清华大学联盟)的自主招生(AAA,或“高水平大学自主选拔学业能力测试”)。我通过了初试并被清华大学交叉信息研究院面试。这是一份面试的转录。

去 THU IIIS 面试