Suppose Alice wants to securely communicate with Bob securely, and she has Bob's public key, which she obtained via mobile phone. They need to exchange many large messages, including pictures and videos. However, their phones are somewhat outdated, and they cannot perform the computationally intensive modular operations (such as exponentiation) required for public key encryption over large datasets. Is it possible for them to set up a one-time, efficient, secure communication method? (Hint: remember that operations like (XOR) which are used in symmetric key encryption, are extremely efficient)