2.21 In one of Dorothy Sayers"s mysteries, Lord Peter is confronted with the message shown in Figure 2.9. He also discovers the key to the message, which is a sequence of integers:
787656543432112343456567878878765654
3432112343456567878878765654433211234
a. Decrypt the message. Hint: What is the largest integer value?
b. If the algorithm is known but not the key, how secure is the scheme?
c. If the key is known but not the algorithm, how secure is the scheme?
