Problem 1 (Authentication): Consider the following authentication protocol, which uses a classical cryptosystem. Alice generates a random message r, enciphers it with the key k she shares with Bob, and sends the enciphered message {r}k to Bob. Bob deciphers it, adds 1 to r, and sends {r + 1}k back to Alice. Alice deciphers the message and compares it with r. If the difference is 1, she knows that her correspondent shares the same key k and is therefore Bob. If not, she assumes that her correspondent does not share the key k and so is not Bob. Does this protocol authenticate Bob to Alice? If so, Why? Otherwise, explain why not.

Check the explanation

Explanation:

Yes, going by the question above, the protocol validates Bob to Alice for the reason that the key is only shared between Bob and Alice as well as the number which is being sent randomly. Therefore the invader won’t be able to predict and response to that number. Because of the authentication protocol, that makes use of a classical cryptosystem thereby resulting into the possibility of an argument such that key finding is attainable via invader.

the benefits of raising bc’s minimum wage to $15 through a

series of pre-announced staged increases far outweigh the likely

costs. claims that such an increase will lead to massive job losses

in low-wage sectors of the economy are not credible.

• an increase to $15 would result in some job losses. however,

the likely impact is less than a 1 per cent reduction in the overall

provincial employment rate, and a 7.6 per cent reduction in the

employment rate for those currently making between $10.25

and $15 per hour.

• the large job loss impacts predicted by some opponents of

minimum wages misrepresent the existing economic research. in

reading and using that research, it is important to recognize that

estimates showing job loss effects of minimum wage increases

apply only to teenagers. estimated effects for young adult and

adult workers range from insignificant to non-existent.

• focusing on teenage workers plays up an inaccurate stereotype

about who earns very low wages in bc and leads to exaggerated

claims about job losses. only 26 per cent of those currently making

between $10.25 and $12 are teenagers, and only 5 per cent

of those making between $12 and $15 are teenagers.