Update README.md

Reduce unnecessary code

Reduced code

Use blake3 for keystream generation

Switched to BLAKE3 over SHA-256

Updated StreamCrypt and README

Update README.md

Add test.png used for example

Add boredhash.py

Update cipher_block.py to import from boredhash.py

Update README.md

Update README.md

Update README.md

Uploaded block cipher script

Update README.md