Assume an extended keyboard that uses Extended-ASCII (Extended-ASCII: each character is encoded by 9 bits, and we have 512 characters). 1- What will be the key size (how many keys) of 7 letters password, considering that our cryptosystem accepts the keys in the form of passwords? 2- Assuming only the 20 lowercase letters from the alphabet are used rather than the full 9 bits of the Extended-ASCII encoding. What is the equivalent key length in bits in this scenario? 3- What is the minimum number of characters/letters that are needed for the password to generate a key that has 256 bits length when each letter consists of 9-bit characters? 4- What will be the minimum number of characters/letters when each letter consists of 20 lowercase letters from the Extended-ASCII?