# RSA Cryptosystem

This question is regarding the RSA cryptosystem.

Alice gives Bob her public key, $N$ and $e$, on a USB flash drive. Unfortunately, Bob loses the flash drive on the train.

Question 1: Does Alice need to generate a new key pair? Justify your answer.

After hearing of Bob’s carelessness, Alice sends her public key to Bob in an unencrypted email.

Question 2: Explain how Eve, with the ability to intercept and modify messages, could eavesdrop on their conversations without either of them knowing. Why would this not be a problem if Bob hadn’t lost the flash drive?

Could I have help in answering these questions.

This is my thought on question 1: I would think Alice does not need to generate a new Public Key, since if anyone picks up the flash drive they still do not know the Private key which is difficult to determine with just $N$ and $e$. They can send Alice messages, but can't decrypt the ciphertext sent to Alice.

• – mikeazo Jan 17 '17 at 20:39