Please write your code in R and submit your script and results for each of the following. Use the functions expand() and S1_function() to do the following:

USE THE FOLLOWING Function:

expand <- function(v) { ev <- vector(mode = "character") swap(v[3], v[4]) ev[1:4] <- v[1:4] ev[5:8] <- v[3:6] return(ev) } v

S11_function <- function(b) { b <- unlist(strsplit(b, "")) tempVal <- unbinary(paste(b[2:4], collapse = '')) tempRet <- ifelse((b[1] == "0"), S11[tempVal + 1], S12[tempVal + 1]) return(tempRet) } S11_function("1110")

QUESTION :

Create a second function for substitution box S2_function() that replicates the S1_function() your wrote for homework 4 except that it uses the following substitution boxes: S11 contains the binary of the numbers (4, 0, 6, 5, 7, 1, 3 2) and S12 contains those for (5, 3, 0, 7, 6, 2, 1, 4). (20 points)

Create a round function called round1() that takes a binary character vector of length 12 and key K of length 9 and does the following: (20 points total)

Divide the block into two equal halves called L0 and R0.

Create two sub keys K1 containing the first 8 digits of K and K2 that contains the last 8 digits of K.

Expand R0 from 6 t o 8 bits and call it ER0.

Take the XOR of the result of ER0 with K1. Store the first 4 bits in a variable called block1 and the last 4 bits in a variable called block2.

Call S1_function with block1 as its parameter.

Call S2_function with block2 as its parameter.

Concatenate the results of e) and f) and store the result in a variable called FR0.

Take the XOR of FR0 and L0 and store the results in R1.

Store R0 to L1.

Return L1 concatenated to R1.