without knowledge of the secret key k. (A"c has the ability to choose a ciphertext and then obtain its decryption. Here, you have 128 plaintext/ciphertext pairs to work with and you have the ability to chose the value of the ciphertexts) en iphertext" means that an adversary Note: The following problems refer to simplifed DES, described in Appendix G 3.16 Refer to Figure G.2, which depicts key generation for S-DES 3.17 The equations for the variables q and r for S.DES are defined in the section on 3.18 Using S-DES, decrypt the string (10100010) using the key (0111111101) by hand. a. How important is the initial P10 permutation function? b. How important are the two LS-1 shift functions? S-DES analysis. Provide the equations for s and t Show intermediate results after each function (IP, Fx SW, FK.IP).Then decode the first 4 bits of the plaintext string to a letter and the second 4 bits to another letter where we encode A through P in base 2 (ie.. A(xxx). I. 0001,-.-. P-11 ii ). Hint: As a mid- way check, after the application of SW, the string should be (00010011). Programming Problems 3.19 Create software that can encrypt and decrypt using a general substitution block cipher 3.20 Create software that can encrypt and decrypt using S-DES Test data: use plaintext ciphertext, and key of Problem 3.18. All students: Write a program in MATLAB or C/C++ that can encrypt and decrypt using S-DES (simplified DES) Test data: Use plaintext, ciphertext and the key of problem 3.18. Put comments on your program script and send me a zip file with all of the program files and your results (output screen capture) pages, with your name as the file name without knowledge of the secret key k. (A"c has the ability to choose a ciphertext and then obtain its decryption. Here, you have 128 plaintext/ciphertext pairs to work with and you have the ability to chose the value of the ciphertexts) en iphertext" means that an adversary Note: The following problems refer to simplifed DES, described in Appendix G 3.16 Refer to Figure G.2, which depicts key generation for S-DES 3.17 The equations for the variables q and r for S.DES are defined in the section on 3.18 Using S-DES, decrypt the string (10100010) using the key (0111111101) by hand. a. How important is the initial P10 permutation function? b. How important are the two LS-1 shift functions? S-DES analysis. Provide the equations for s and t Show intermediate results after each function (IP, Fx SW, FK.IP).Then decode the first 4 bits of the plaintext string to a letter and the second 4 bits to another letter where we encode A through P in base 2 (ie.. A(xxx). I. 0001,-.-. P-11 ii ). Hint: As a mid- way check, after the application of SW, the string should be (00010011). Programming Problems 3.19 Create software that can encrypt and decrypt using a general substitution block cipher 3.20 Create software that can encrypt and decrypt using S-DES Test data: use plaintext ciphertext, and key of Problem 3.18. All students: Write a program in MATLAB or C/C++ that can encrypt and decrypt using S-DES (simplified DES) Test data: Use plaintext, ciphertext and the key of problem 3.18. Put comments on your program script and send me a zip file with all of the program files and your results (output screen capture) pages, with your name as the file name