Suppose AES (or any block cipher) is used to encrypt data. Which mode of encryption covered in class is best suited for each of the following two scenarios and why? If more than one mode is suitable, pick one and explain why.

a. Streaming video between a server and client.

b. Disk encryption on a backup server storing system log files where the files are individually encrypted with one key used across all files. In addition, answer the following: Consider the first block of each encrypted file and the fact that the same key was used, what is the implication of this?