Consider the following protocol between Alice $($sender$)$ and Bob $($receiver$)$:

Both parties have already agreed on the choice of a strong cryptographic hash function H $($e$.$g$.$ SHA$-512),$ and the choice of a strong public key cipher E$,$ e$.$g$.$ RSA$-4096.$

They have also agreed on a digital signature scheme with message recovery.

Alice has a private$-$public key pair of $(,$

$)$ and Bob has a private$-$public key pair of $(,$

$)$

Only Alice knows $$

and only Bob knows $$

Both $$

and $$

are publicly known

Alice $($the sender$)$ performs the following on her message $$

$,$ and sends the output, $$

$,$ to Bob over a public channel:

$=()||()||$

$()$

represents the public$-$key encryption of a message $$

with public$-$key of $$

using encryption algorithm $$

;

$()$

represents the cryptographic Hash of the message $$

using hash function $$

;

and x$1||$ x$2$ represents simple concatenation $($appending$)$ of the two messages x$1$ and x$2$ together.

$$

is an identifier unique to Alice

Select all answers that apply. Incorrect answers are marked negatively!

The protocol provides the ability to detect accidental errors

The protocol provides entity authentication $-$ that is$,$ Bob is sure he has received a fresh message and is sure it originates from Alice

Bob has data origin authentication on the message he receives from Alice

Alice can be sure her message to Bob is confidential $-$ no one other than Bob can view it

The protocol does not provide confidentiality, because anyone can use Bob's public key to decrypt it

The protocol does not provide Non$-$Repudiation

Bob responds to Alice with his own message as follows.

$=()||()||$

$()$

represents a digital signiature on message $$

with private$-$key of $$

using the signature algorithm $$

$.$ They are using a digital signature algorithm with message recovery

$$

is a random number generated by Bob

Select all answers that apply!

Alice can respond to Bob with a message that Bob can be sure is fresh

The protocol provides non$-$repudiation on Bob's message $-$ he cannot deny sending it

Alice has data origin authentication on the message she receives from Bob

Alice is sure the message from Bob is fresh due to rB

The protocol does not provide data integrity on message m

The message is confidential, only Alice can read it