public int[] Decrypt(int[] input, int[] key)
{
//Need to be implemented
//Decryption is simply the inverse of encryption, follwing the same steps as above, but reversing the order in which the subkeys are applied.
//Taking Input class to store the message
DES_implementation3.Input inputClass = new DES_implementation3.Input();
//input after initial permutation;
inputClass.getInput(initialPermutation(input));
//Getting all the subkeys
int[,] subkeys = generateKeys(key, 2);
//There are only 2 round in this encryption so
//making 2 rounds of for()
for (int i = 2; i > 0; i--)
{
//The function for each round should be R[i+1] = des.xor(L[i], des.F(R[i], des.getSubKet(subkeys, i+1));
//Then L[1] = R[0];
int[] tempR0 = inputClass.R;
inputClass.R = xor(inputClass.L, F(inputClass.R, getSubKey(subkeys, i)));
inputClass.L = tempR0;
}
//R2 goes to Left
inputClass.R.CopyTo(inputClass.input, 0);
//L2 goes to Right
inputClass.L.CopyTo(inputClass.input, inputClass.L.Length);
//Reverse IP
inputClass.getInput(reverseInitialPermutation(inputClass.input));
return inputClass.input;
}
/// <summary>
/// This method will need:
/// 1. a codeblock of 16bits
/// 2. 16bits key
///
/// </summary>
/// <returns>Encrypted binary 16bits message </returns>
public int[] Encrypt(int[] input, int[] key)
{
//Taking Input class to store the message
DES_implementation3.Input inputClass = new DES_implementation3.Input();
//input after initial permutation;
inputClass.getInput(initialPermutation(input));
//Getting all the subkeys
int[,] subkeys = generateKeys(key, 2);
//There are only 2 round in this encryption so
//making 2 rounds of for()
for (int i = 0; i < 2; i++)
{
//The function for each round should be R[i+1] = des.xor(L[i], des.F(R[i], des.getSubKet(subkeys, i+1));
//Then L[1] = R[0];
int[] tempR0 = inputClass.R;
inputClass.R = xor(inputClass.L, F(inputClass.R, getSubKey(subkeys, i + 1)));
inputClass.L = tempR0;
}
//R2 goes to Left
inputClass.R.CopyTo(inputClass.input, 0);
//L2 goes to Right
inputClass.L.CopyTo(inputClass.input, inputClass.L.Length);
//Reverse IP
inputClass.getInput(reverseInitialPermutation(inputClass.input));
return inputClass.input;
}
public void testFullEncryption2()
{
//Input "JZ"
int[] input = new int[] {
0,1,0,0,1,0,1,0,
0,1,0,1,1,0,1,0
};
DES_implementation3.Input inputclass = new DES_implementation3.Input();
//input after initial permutation;
inputclass.getInput(des.initialPermutation(input));
//Random key
int[] key = new int[] {
0, 1, 1, 0, 1, 1, 0, 1,
0, 0, 1, 0, 0, 0, 1, 1
};
//Getting all the subkeys
int[,] subkeys = des.generateKeys(key, 2);
//There are only 2 round in this encryption so
//making 2 rounds of for()
for (int i = 0; i < 2; i++)
{
//By the formula F(R[i], K[i+1]
//des.F(r, des.getSubKey(subkeys, ));
//The function for each round should be R[i+1] = des.xor(L[i], des.F(R[i], des.getSubKet(subkeys, i+1));
//Then L[1] = R[0];
int[] subkey = des.getSubKey(subkeys, i + 1);
int[] funkcija = des.F(inputclass.R, subkey);
int[] tempR0 = inputclass.R;
inputclass.R = des.xor(inputclass.L, funkcija);
inputclass.L = tempR0;
}
//before reverse initial permutation
int[] resultarrayR2 = new int[] {
1, 1, 1, 0,
1, 1, 0, 1 };
//R2 goes to Left
inputclass.R.CopyTo(input, 0);
//L2 goes to Right
inputclass.L.CopyTo(input, inputclass.L.Length);
//Reverse IP
inputclass.getInput(des.reverseInitialPermutation(input));
//after encryption
int[] resultarray2 = new int[]{
0, 1, 0, 1,
1, 1, 0, 1,
0, 0, 0, 1,
0, 1, 1, 0
};
CollectionAssert.AreEqual(resultarray2, inputclass.input);
}