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rc4.cs
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rc4.cs
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using System;
using System.Collections.Generic;
static class RC4
{
static void Main(string[] args)
{
// Operating on a 3-bit key as an example.
var k = new int[] { 2, 6, 1, 5 };
var text = new int[] { 1, 3, 1, 2 };
var s = new List<int>() { 0, 1, 2, 3, 4, 5, 6, 7 };
var t = new List<int>() { 2, 6, 1, 5, 2, 6, 1, 5 };
KSA(s, t);
var temp = PRGA(s, text);
Console.Write("Cipher = [");
foreach (var element in temp)
{
Console.Write(element + " ");
}
Console.WriteLine("]");
}
public static List<int> PRGA(List<int> s_list, int[] text)
{
int i = 0, j = 0;
var cipher = new List<int>();
for(int index = 0; index < text.Length; index++)
{
i = (i + 1) % 8;
j = (j + s_list[i]) % 8;
s_list.Swap(i, j);
var t = (s_list[i] + s_list[j]) % 8;
var k = s_list[t];
cipher.Add(k ^ text[index]);
}
return cipher;
}
public static void KSA(List<int> s_list, List<int> t_list)
{
var j = 0;
for (int i = 0; i < 8; i++)
{
j = (j + s_list[i] + t_list[i]) % 8;
s_list.Swap(i, j);
}
}
public static void Swap(this List<int> list, int i, int j)
{
var temp = list[i];
list[i] = list[j];
list[j] = temp;
}
}