Complete the implementation of a Diffie-Hellman-style key exchange protocol in /app/encrypt.py .

Complete the implementation of a Diffie-Hellman-style key exchange protocol in /app/encrypt.py .: a task in rts-1k-rootless-apptainer: RTS-1K: offline rootless Apptainer release (Harbor dataset). What the agent is asked, how it is graded, what it runs in, and its files.