# Randomization 1
![](https://raw.githubusercontent.com/deut-erium/WriteUps/master/HSCTF/crypto/Randomization%201/Capture.PNG)
The challenge is to somehow predict the random numbers the binary is generating.
Decompilation of main in ghidra shows that we need to predict the next number 10 times.
![](main.png)
The next random number is generated from the `next` function.
When you decompile that function in ghidra, you can see it's a simple pseudorandom function.
![](pseudo.png)
We can easily implement this in python.
```pythonn = (n * ord('%') + 0x41) % 256 ## pseudorandom function```
We can connect to the server using pwntools, leak the first number, and send 10 numbers using the pseudorandom function to get the flag.
Flag: `flag{l1n34r_c0n6ru3n714l_63n3r470r_f41lur3_4b3bcd43}`