B$.$ Alice works for a$,$ financial company. She regularly works from home and transfers

files of private$/$sensitive financial data between her home computer and the

company$$s file server, Bob, which is connected to the Internet through the

company$$s network. The files transferred often contain large amounts of data.

$1.$ Identify two security requirements for the protection of communications

between Alice and Bob, and explain why these two requirements are essential.

$2$

$2.$ Design a secure communication protocol that allows:

$$ Alice to request a private file from Bob

$$ Bob to respond by sending the requested file to Alice, where both

symmetric and asymmetric $($or public$-$key$)$ cryptosystems including

secure hash functions are available for the protocol design.

$$ Explain how the designed protocol operates.

$3.$ Justify how the protocol produced in B $(2)$ satisfies each of the two security

requirements identified in B $(1).$