Calculate the Key Space for all the systems given below and explain if it is possible to use brute force technique to decrypt the cipher text without knowing the Key.

1- A Feistel Structure based Cipher in which the plain text block is 32 bits and the Key size 128 bits

." importint note Please add an explanation for each point "

- Key Space:

- Possibility of using brute force technique to decrypt the cipher text without knowing the Key :

2- A Simple Substitution Cipher in which we use only 10 Characters.

- Key Space:

-Possibility of using brute force technique to decrypt the cipher text without knowing the Key :

3- An affine Cipher with 32 characters.

- Key Space:

- Possibility of using brute force technique to decrypt the cipher text without knowing the Key :