# Shark

Shark is a sha256+xor based encryption.  
I made it because I want to try to break it.  
(Precisely: Show it does not provide semantic security, because it is not IND-CPA-secure)  
This will work iff I succeed in building a PPT-discriminator for sha256 from randomness  
As my first approach this discriminator will be based on an LSTM-network.  
Update: This worked out way better than expected; given long enought sequences (128 Bytes are more than enough) we can discriminate successfully in 100% of cases.  
Update: I did an upsie in the training-code and the discriminator is actually shit.