# decrypt to me Writeup
### ISITDTU Quals 2019 - crypto 395 - 42 solves
> decrypt to me?????
#### Observations
The seed of a given random number generator is the length of flag. By observing the code, length of ciphertext and plaintext are the same. Therefore I directly obtain the seed of [prng](https://en.wikipedia.org/wiki/Pseudorandom_number_generator) and decrypt(XORing ciphertext and random number output bit by bit) to get the flag. I get the flag:```ISITDTU{Encrypt_X0r_N0t_Us3_Pseud0_Rand0m_Generat0r!!!!!}```
Given ciphertext: [config.py](config.py)
Encryption code: [task.py](task.py)
Exploit code: [solve.py](solve.py)