---
# System prepended metadata

title: KashiCTF 2025

---

KashiCTF 2025  
# Playing with number  
Given:  
![image](https://hackmd.io/_uploads/rJ8i4eYq1x.png)  
I used matrix multiplication and Caesar cipher to obtain the flag  
Solve script:  
```python= 
import numpy as np
A = np.array(
[[-103.08333333, -40.5, 42.58333333],
[-131.25, -52.5, 54.75, ],
[-81.41666667, -34.5, 34.91666667],
[-91.58333333, -36.5, 39.08333333],
[-25.25, -10.5, 11.75, ],
[-63.5, -28., 26.5, ],
[-60.33333333, -25., 26.33333333],
[-12.75, -4.5, 7.25, ],
[-151.08333333, -62.5, 63.58333333]]
    )
s='abcdefghijklmnopqrstuvwxyz'
B = np.array([[2, 4, -1], [3, -6, 1], [8, 4, -1]])

C = np.dot(A,B)
for i in C:
    for j in i:
        print(s[(round(j)-1)%26],end='')
#print(C)
#matrixmultiplicationiseasyy
```
# Old Diner  
given:  
![upload_4d678cb0553f4e6d6e38e116a4ccdb36](https://hackmd.io/_uploads/SkkgmG59ye.png)  
search `diner that served ice cream with coke, Greek omlette`:  
![upload_2ef13ae9ac7955c97b4b23c9c70c5b2a](https://hackmd.io/_uploads/rykDQG9c1e.png)  
I found: `Lexington Candy Shop`  
![upload_d3781bb2279618977afd1776ea67f819](https://hackmd.io/_uploads/r1duNMqc1l.png)  
then i found:  
https://www.tripadvisor.com/ShowUserReviews-g60763-d522599-r737610550-Lexington_Candy_Shop-New_York_City_New_York.html  
![image](https://hackmd.io/_uploads/r18n4zq9kg.png)  
![image](https://hackmd.io/_uploads/BJsANz9qyx.png)  
Flag: `KashiCTF{Lexington_Candy_Shop_41.65}`  

# Kings  
![image](https://hackmd.io/_uploads/SJKISM59kl.png)  
Given:  
![upload_fc92c3c3435635e53c7563f6affb2b9d](https://hackmd.io/_uploads/SkUKBf951g.png)  
It's in `State Hermitage Museum in Saint Petersburg, Russia`:  
![upload_51df21ed8815b14b973af6d460f6ee7d](https://hackmd.io/_uploads/Bkf_8f55ke.png)  
Flag: `KashiCTF{59.9399_30.3149}`  
# Stego Gambit  
![image](https://hackmd.io/_uploads/S1efPz95kg.png)  
Given:  
![chall(3)](https://hackmd.io/_uploads/HkJXvf991l.jpg)  
Best move is: `1. Bh1 Kxa2 2. Qg2#`  
![image](https://hackmd.io/_uploads/Bypvwz5cJg.png)  
Flag: `KashiCTF{573g0_g4m617_4cc3p73d}`  