A scheme developed by Whit Diffie, Martin Hellman, and Ralph Merkle is commonly called “Diffie‑Hellman”. What does this scheme directly enable? 

See the previous question. Describe in words the inverse of the operation performed above.

See the previous question. Explain what Charlie would attempt to do to perform this type of attack.  Your answer must be specific to the scenario described. 

An organization has a large amount of ciphertext that was encrypted long ago using DES.  The organization is now using the Triple DES Encryption Algorithm (TDEA). An employee has access to some DES ciphertext and the key used to encrypt it.  What is the best way for the employee to decrypt this ciphertext?

Suppose that a hacker is able to log into the administrative account for a webserver and change the configuration so that it does not accept incoming connections.  The hacker’s actions are an attack on the of the webserver.  Hint: The answer is the name of a cybersecurity service. 

Alice generates a pseudorandom key and uses it with a symmetric cipher scheme to encrypt a message for Bob.  Explain what she should do to send the key to Bob over an insecure communications channel (e.g. the Internet).

A security mechanism is called “specific” because …

Counter mode encryption/decryption is relatively fast because …

Let and . Find each of the following. Use ^ to indicate exponents. To type a fraction (if any), enclose the numerator in its own set of parentheses, and enclose the denominator in its own set of parentheses. Use / for the fraction bar. Do not use spaces. a) b) c) d) e) f)

The following graph was created by horizontally shifting the graph of the basic function . Write a function that describes the graph. Do not include f(x)=. Use | for absolute value bars. Do not space.