Block Cipher

Question:

1. Let temp_block denote a Sage variable that contains the output of the first application of function fK (f_K  in the Sage example code) while encrypting with Simplified DES.  Using  subroutines from the example sage Code, write sage code to recover the  input block passed to Simplifed DES Decrypt.  Meaning reverse the first  steps in Simplified DES Encrypt. You may assume that you have the first  round key in a variable K1.
2. Using subroutines from the Sage example code for Simplified DES, write a function to compute Simplified DES Decrypt.