update algorithm for DHKE

ASYD_Cryptograhpy/SW03-DHKE/main.c

@@ -8,7 +8,7 @@
  * \author        Basil Estermann, basil.estermann@stud.hslu.ch
  *                Simon Frei, simon.frei@stud.hslu.ch
  *                Jonas Arnold, jonas.arnold@stud.hslu.ch
- * \date          10.03.2023
+ * \date          14.03.2023
  *
  *--------------------------------------------------------------------
  */
@@ -23,51 +23,122 @@
 
 #define KEY_LENGTH 64
 
+int createKeypair(void);
+int calculateSessionKey(void);
+
 void main(void) {
 
-    /* Initialize variables */
+    printf("------ Calculate Keypair ------\n\n");
+    int result = createKeypair();
+    if (result != 0) {
+        return result;
+    }
+
+    printf("------ Calculate Sessionkey ------\n\n");
+    result = calculateSessionKey();
+    if (result != 0) {
+        return result;
+    }
+
+    return 0;
+}
+
+int createKeypair(void) {
+    /*** CREATE KEYPAIR ***/
+    const char* P_string = "3203431780337000";
+    const char* alpha_string = "AFFE425634534";
+    const char* Priv_a_string = "9778729279583412";
+    const char* Priv_b_string = "4825234752983495";
 
     // P has to be a prime number! Large prime number (64bit): 3203431780337000
     t_encryptionArithmetic P;
     encryptionArithmetic_Init(&P, KEY_LENGTH);
-    if (encryptionArithmetic_stringToHex("3203431780337000", P.number, KEY_LENGTH) == false) {
+    if (encryptionArithmetic_stringToHex(P_string, P.number, KEY_LENGTH) == false) {
         printf("ERROR: Creating P.");
         return 1000000;
     }
 
-    // alpha not required for session key generation
-    //t_encryptionArithmetic alpha;
-    //encryptionArithmetic_Init(&alpha, KEY_LENGTH);
-    //if (encryptionArithmetic_stringToHex("13", alpha.number, KEY_LENGTH) == false) {
-    //    printf("ERROR: Creating alpha.");
-    //    return 1000001;
-    //}
-
-    t_encryptionArithmetic pub;
-    encryptionArithmetic_Init(&pub, KEY_LENGTH);
-    if (encryptionArithmetic_stringToHex("1370122177720875", pub.number, KEY_LENGTH) == false) {
-        printf("ERROR: Creating pub.");
-        return 1000002;
+    t_encryptionArithmetic alpha;
+    encryptionArithmetic_Init(&alpha, KEY_LENGTH);
+    if (encryptionArithmetic_stringToHex(alpha_string, alpha.number, KEY_LENGTH) == false) {
+        printf("ERROR: Creating alpha.");
+        return 1000001;
     }
 
-    t_encryptionArithmetic priv;
-    encryptionArithmetic_Init(&priv, KEY_LENGTH);
-    if (encryptionArithmetic_stringToHex("9778729279583412", priv.number, KEY_LENGTH) == false) {
-        printf("ERROR: Creating priv.");
+    t_encryptionArithmetic priv_a;
+    encryptionArithmetic_Init(&priv_a, KEY_LENGTH);
+    if (encryptionArithmetic_stringToHex(Priv_a_string, priv_a.number, KEY_LENGTH) == false) {
+        printf("ERROR: Creating priv a.");
         return 1000003;
     }
 
-    t_encryptionArithmetic session_key;
-    encryptionArithmetic_Init(&session_key, KEY_LENGTH);
+    t_encryptionArithmetic priv_b;
+    encryptionArithmetic_Init(&priv_b, KEY_LENGTH);
+    if (encryptionArithmetic_stringToHex(Priv_b_string, priv_b.number, KEY_LENGTH) == false) {
+        printf("ERROR: Creating priv b.");
+        return 1000004;
+    }
+
+    /* initialize and calculate public key a */
+    t_encryptionArithmetic pub_a;
+    encryptionArithmetic_Init(&pub_a, KEY_LENGTH);
+    squareAndMultiply(&alpha, &priv_a, &P, &pub_a, KEY_LENGTH);
 
+    /* initialize and calculate public key b */
+    t_encryptionArithmetic pub_b;
+    encryptionArithmetic_Init(&pub_b, KEY_LENGTH);
+    squareAndMultiply(&alpha, &priv_b, &P, &pub_b, KEY_LENGTH);
 
-    /* Create session key */
-    squareAndMultiply(&pub, &priv, &P, &session_key, KEY_LENGTH);
 
+    /* initialize and calculate session key for person a */
+    t_encryptionArithmetic session_key_a;
+    encryptionArithmetic_Init(&session_key_a, KEY_LENGTH);
+    squareAndMultiply(&pub_b, &priv_a, &P, &session_key_a, KEY_LENGTH);
+    printf("Calculated session key for person A: 0x%x\n", *session_key_a.number);
+
+    /* initialize and calculate session key for person b */
+    t_encryptionArithmetic session_key_b;
+    encryptionArithmetic_Init(&session_key_b, KEY_LENGTH);
+    squareAndMultiply(&pub_a, &priv_b, &P, &session_key_b, KEY_LENGTH);
+    printf("Calculated session key for person B: 0x%x\n", *session_key_b.number);
+
+    return 0;
+}
 
-    /* Write session key */
-    printf("%i",*session_key.number);
+int calculateSessionKey(void) {
+
+    /*** Calculate Session Key ***/
+    const char* P_string = "B8C6440FA3B64CB9"; 
+    const char* Priv_a_string = "C8B2014E72001DD";
+    const char* Pub_b_string = "69DF372122D2E892";
+
+    // P has to be a prime number! Large prime number (64bit): 3203431780337000
+    t_encryptionArithmetic P;
+    encryptionArithmetic_Init(&P, KEY_LENGTH);
+    if (encryptionArithmetic_stringToHex(P_string, P.number, KEY_LENGTH) == false) {
+        printf("ERROR: Creating P.");
+        return 1100000;
+    }
+
+    t_encryptionArithmetic priv_a;
+    encryptionArithmetic_Init(&priv_a, KEY_LENGTH);
+    if (encryptionArithmetic_stringToHex(Priv_a_string, priv_a.number, KEY_LENGTH) == false) {
+        printf("ERROR: Creating priv a.");
+        return 1100003;
+    }
+
+    t_encryptionArithmetic pub_b;
+    encryptionArithmetic_Init(&pub_b, KEY_LENGTH);
+    if (encryptionArithmetic_stringToHex(Pub_b_string, pub_b.number, KEY_LENGTH) == false) {
+        printf("ERROR: Creating pub b.");
+        return 1100004;
+    }
 
+    /* initialize and calculate session key for person a */
+    t_encryptionArithmetic session_key_a;
+    encryptionArithmetic_Init(&session_key_a, KEY_LENGTH);
+    squareAndMultiply(&pub_b, &priv_a, &P, &session_key_a, KEY_LENGTH);
+    printf("Calculated session key for person A: 0x%x\n", *session_key_a.number);
 
     return 0;
 }