Compare two proposals for secure email systems:

Proposal 1: send the message enciphered in AES, and the AES key enciphered in RSA using the recipient's public key.

Proposal 2: Encipher the message in RSA using the recipient's public key.

The advantages of scheme 1 include:

a)	it is faster to encipher and decipher, and easier to send to multiple recipients

b)	it verifies the sender's identity and ensures that the message is not altered in transit

c)	it is deniable, so the sender can later claim to have written something else

d)	if Eve can break RSA, she still cannot read the message because of the AES encipherment