1. What is the size of the key space if all 8 characters are randomly chosen 8-bit ASCII characters? How long does an average key search take with a single PC?
2. How many key bits are used, if the 8 characters are randomly chosen 7-bit ASCII characters (i.e., the most significant bit is always zero)? How long does an average key search take with a single PC?
3. How large is the key space if, in addition to the restriction in Part 2, only letters are used as characters. Furthermore, unfortunately, all letters are converted to capital letters before generating the key in the software. How long does an average key search take with a single PC?