Q$4$ AND Q$5$: In this problem we explore the relationship between password length and

cryptographic security.

Suppose a password consists of $7$ ASCII characters. You can review the ASCII characters

here.. Exactly $2^7=128$ of these codes are for printable characters; we will assume every

character in the password is printable.

What is the size of the keyspace that consists of passwords of this form?

What is the equivalent key length in bits?

Assuming that you

could check one password every ${10}^{-9}$ seconds, what is the worst case running time for

cracking this password by brute force search $($in days$)?$

assume that the user used only $29$ characters from the keyboard. What is the key length in

bits in this case?

How many days, in the worst case, would it

take to break this weaker password? You can't round to the nearest day here $--$ be as exact

as possible.

Supposing you used only $29$ characters, how long

is the shortest password that achieves $168$ bits of security?