Please help with this question. Write a simple code for it . Thank you

(6 marks) Let K be a fixed element of Z26, and define the fixed permutation ? over Z26 as 0 12 3 4 5 67 8 9 10 1 12 13 14 15 16 17 18 19 20 21 22 23 24 25 23 13 24 0 7 15 14 6 25 16 22 19 18 5 17 2 21 12 20 4 10 938 1 29 Consider the stream cipher with the key stream element ? ? z26, where zi = (K +1-1) mod 26. Encryption and decryption using ? are done as follows: e,(z) = (r(z) + z) mod 26, d,(y) = (?-1(y-z) mod 26). Write a C/C++program streamCipher to decrypt the following ciphertext which was encrypted by the above stream ipher WRTCNRLDSAFARWKXFTXCZRNHNYPDTZUUKMPLUSOXNEU DOKLXRMCBKGRCCURR