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# The Foreign Student

*Tarbiat Modares University has a foreign student. His name is Zedmondo. He has a* very shady character. He always walks alone, eats alone, and never talks much.There are some rumors about him. Some people say he is a genius sociopath; some say he is just too self-involved. But one thing is obvious; he has a secret.Once, one of the students heard that he was talking about receiving some important documents via a private email. Maybe if we find his email, we can learn about his secret.*

---

题目是要我们找一个叫`Zedmondo`的大学生的`private email`

首先,用Google搜索`Zedmondo Tarbiat Modares University`,找到这个人的[Linkedin主页](https://ir.linkedin.com/in/zedmondo-zaberini-203b33206)

![Zedmondo 领英](https://github.com/ZhaoQi99/CTF-Writeups/raw/main/TMUCTF2021/Osint/assets/linkedin.png)

除了一个Github链接外([https://github.com/ZedZini](https://github.com/ZedZini)),没有什么其他有价值的信息

浏览Github上的仓库,结合题目中的`he has a secret.`,一个仓库[https://github.com/ZedZini/secretkey](https://github.com/ZedZini/secretkey)的`README`引起了我的注意.

```
# secretkey
It is a public key. Not really a secret, right?!
```
与`README`一起的还有一个[PGP公钥文件](https://github.com/ZedZini/secretkey/blob/main/0xEB0B6528-pub.asc):
```
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: Keybase OpenPGP v1.0.0
Comment: https://keybase.io/crypto

xsFNBGAqSQ8BEADZtFG6grS2QP9afsA7SmT85TpxcSmG5LGLmSHKgI47ZwS+dPrO
SzChR0Jt3vI7BjA3WVlxQp94XTqRqFrjtJkS2I3nO3I94jhLu0AwfoiskKzyl+tQ
...
-----END PGP PUBLIC KEY BLOCK-----
```

访问[https://keybase.io/crypto](https://keybase.io/crypto),发现网站上已经给出了使用说明:

```shell
Using the Keybase command line app
keybase pgp encrypt -m "message" [them]
With GPG or another PGP program
You may import from Keybase to GPG easily and then perform whatever cryptographic actions you want.

# using curl
curl https://keybase.io/[them]/key.asc | gpg --import

# using `keybase pgp pull` which
# imports to GPG key chain for you
keybase follow [them]
keybase pgp pull [them]
```

参照使用说明:

```shell
curl https://raw.githubusercontent.com/ZedZini/secretkey/main/0xEB0B6528-pub.asc | gpg --import

% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0
gpg: 目录‘/Users/zhaoqi219/.gnupg’已创建
gpg: 钥匙箱‘/Users/zhaoqi219/.gnupg/pubring.kbx’已创建
100 6139 100 6139 0 0 4494 0 0:00:01 0:00:01 --:--:-- 4490
gpg: /Users/zhaoqi219/.gnupg/trustdb.gpg:建立了信任度数据库
gpg: 密钥 586DD615EB0B6528:公钥 “Zedmondo Zaberini (Nothing to say...) <[email protected]>” 已导入
gpg: 处理的总数:1
gpg: 已导入:1
```

**flag:** `TMUCTF{[email protected]}`

Original writeup (https://github.com/ZhaoQi99/CTF-Writeups/blob/main/TMUCTF2021/Osint/The_Foreign_Student.md).