From Zero To X

zTrix's Blog

PlaidCTF 2014 - Parlor (Crypto 250) Writeup

by zTrix@blue-lotus

Problem description

Crypto (250 pts)

The Plague is running a betting service to build up funds for his massive empire. Can you 
figure out a way to beat the house? The service is running at

Codegate CTF Final 2014 Memory

Last week, We represented team blue-lotus, consisting of me(zTrix), cbmixx, Aluex, Adrian, fqj and our beautiful photographer as well as translator, at Codegate CTF Finals 2014, in Seoul, South Korea. It’s really a wonderful experience.

Since we are close to Seoul, we took off at April 1st, just one day before the game.

Let’s Make License Social! The Star and Thank Author License (SATA License)

There are many licenses out there for open source software. GPL, MIT License, Apache License are most popular ones among them.

When creating projects on github/google code, there even is an option for people to choose the most popular licenses.

But to me, those licenses are boring, and for most of the time, I think, nobody care about them, very few people can distinguish them. Actually, it’s just put into a project occupying an embarrassing position, maybe just to make a project feels more like a formal one, and in active developing.

Why not make those licenses more interesting, and attach some social functions for developers?

Codegate CTF 2014 Quals - Weirdshark Writeup

by zTrix@blue-lotus

A pcap file is given here for analysis. check type using file

# file weird_shark.pcap_f5f1e42dd398f18c43af89ba972b3ee7
weird_shark.pcap_f5f1e42dd398f18c43af89ba972b3ee7: pcap-ng capture file - version 1.0

Open the file using wireshark, but no luck, wireshark reports malformed file format and refuse to open it.

So we need to extract the packets inside manually.

PHDays CTF IV Quals 2014 - Turututu Writeup

by zTrix@blue-lotus

turututu is an ELF 64-bit executable, after some investigation, it’s easy to find out that the task.exe is a native binary generated using ocamlopt.

I know little about ocaml, so at first I searched a lot trying to get some bytecode or decompiler stuff, or some dedicated debugger for ocaml, but none of these tools could be found.

So it’s time to dive into assembly.

Defcon 20 小记

6 月 2 号到 4 号有幸加入 blue-lotus 参加了 defcon CTF 2012 的比赛,感慨颇深。清华第一次组队参加这个比赛,虽然没进决赛,但第一次参赛能进前 20,也算不错的成绩了。

MooseFS metadata.mfs 数据恢复纪实

从这周四下午到周六早上这 40 个小时真是紧张惊险又刺激。以至于我要写篇 blog 来记录一下。

数据丢失! 天灾人祸!

实验室跑了一套自己的网盘系统,其中后台数据存储用的是 Moosefs 网络分布式文件系统。这个系统用起来一直很好,直到 2 天前…

Trip to the Silicon Valley


3 月 4 号坐上了 Boeing 747,飞机真的很大。人不多,我那一排 3 个座位就我一个人,于是睡得很舒服。






预约是很纠结的一件事情。尤其是我预约的时候是 1 月 19 左右,当时在家,只好请还在北京的同学帮忙去中信银行买了一下加密电话卡,付了签证费用。

第一次打电话还算顺利,准备好各个号码之后,拨通电话,预约日期只有 1 月 27 到 1 月 31 号可以选,2 月好像还没开始。于是预约了 30 号。