Initial Commit

Unique C++ Projects/Hill Cipher Algorithm/Hill CIpher Algo Code.cpp

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+// C++ code to implement Hill Cipher
+#include <bits/stdc++.h>
+using namespace std;    
+string input;
+
+void init_code()
+{
+    #ifndef ONLINE_JUDGE
+    freopen("input.txt", "r", stdin);
+    freopen("output.txt", "w", stdout);
+    #endif // ONLINE_JUDGE
+}
+void Key(string letterkey, int Keymatrix[][3])
+{
+    int k = 0;
+    for (int i = 0; i < 3; i++) 
+    {
+        for (int j = 0; j < 3; j++) 
+        {
+            Keymatrix[i][j] = (letterkey[k]) % 65;
+            k++;
+        }
+    }
+}
+
+
+void encryption(int cipherMatrix[][1],
+             int Keymatrix[][3], 
+             int inputVector[][1])
+{
+
+    for (int i = 0; i < 3; i++) 
+    {
+        for (int j = 0; j < 1; j++)
+        {
+            cipherMatrix[i][j] = 0;
+
+            for (int x = 0; x < 3; x++)
+            {
+                cipherMatrix[i][j] += 
+                     Keymatrix[i][x] * inputVector[x][j];
+            }
+
+            cipherMatrix[i][j] = cipherMatrix[i][j] % 26;
+        }
+    }
+}
+
+void decryption(int outputMatrix[][1],
+             int inverseKeymatrix[][3], 
+             int cipherMatrix[][1])
+{
+
+    for (int i = 0; i < 3; i++) 
+    {
+        for (int j = 0; j < 1; j++)
+        {
+            outputMatrix[i][j] = 0;
+
+            for (int x = 0; x < 3; x++)
+            {
+                outputMatrix[i][j] += 
+                     inverseKeymatrix[i][x] * cipherMatrix[x][j];
+            }
+
+            outputMatrix[i][j] = outputMatrix[i][j] % 26;
+        }
+    }
+}
+
+
+void HillCipher(string message, string letterkey)
+{
+    int Keymatrix[3][3];
+    Key(letterkey, Keymatrix);
+
+    int inputVector[3][1];
+
+    for (int i = 0; i < 3; i++)
+        inputVector[i][0] = (message[i]) % 65;
+
+    int cipherMatrix[3][1];
+    int outputMatrix[3][1];
+    encryption(cipherMatrix, Keymatrix, inputVector);
+
+    string CipherText;
+
+
+    for (int i = 0; i < 3; i++)
+        CipherText += cipherMatrix[i][0] + 65;
+
+
+    cout << "Ciphertext:" << CipherText;
+    int inverseKeymatrix[3][3];
+    for (int i = 0; i < 3; i++)
+    {
+        for (int j = 0; j < 3; j++)
+            cin >> inverseKeymatrix[i][j];
+    }
+    string outputText = "";
+    decryption(outputMatrix,
+             inverseKeymatrix, 
+             cipherMatrix);
+
+    for (int i = 0; i < 3; i++)
+        outputText += outputMatrix[i][0] + 65;
+
+    if (outputText == input)
+    {
+        cout << "\n" << "-----KEY MATCHED!-----" << "\n";
+        cout << "Output:" << outputText;
+    }
+    else
+        cout << "\n" << "SORRY! WRONG KEY";
+}
+
+
+int main()
+{
+    init_code();
+    cin >> input;
+
+    string letterkey = "GYBNQKURP";
+
+    HillCipher(input, letterkey);
+
+
+    return 0;
+}

Unique C++ Projects/Hill Cipher Algorithm/README.md

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+This is a c++ code based on a very famous and efficient crypto security algorithm called Hill Cipher's Algorithm.