Florida_kik is my yt channel sub to it plz

3. bob is arguing that if you use output feedback (ofb) mode twice in a row to encrypt a long message, m, using the same key each time, it will be more secure. explain why bob is wrong, no matter what encryption algorithm he is using for block encryption (15 points).

Write a program which asks you to enter a name in the form of first middle initial last. so you might enter for example samuel p. clemens. use getline to read in the string because it contains spaces. also, apparently the shift key on your keyboard doesn’t work, because you enter it all lower case. pass the string to a function which uses .find to locate the letters which need to be upper case and use toupper to convert those characters to uppercase. the revised string should then be returned to main in the form last, first mi where it will be displayed.

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?