Update DiffieHellman.java

Author: riti2601

src/main/java/com/thealgorithms/ciphers/DiffieHellman.java

@@ -4,20 +4,35 @@
 
 public final class DiffieHellman {
 
-    // Private constructor to prevent instantiation of utility class
-    private DiffieHellman() {
-        throw new UnsupportedOperationException("Utility class");
+    private final BigInteger base;
+    private final BigInteger secret;
+    private final BigInteger prime;
+
+    // Constructor to initialize base, secret, and prime
+    public DiffieHellman(BigInteger base, BigInteger secret, BigInteger prime) {
+        this.base = base;
+        this.secret = secret;
+        this.prime = prime;
     }
 
     // Method to calculate public value (g^x mod p)
-    public static BigInteger calculatePublicValue(BigInteger base, BigInteger secret, BigInteger prime) {
+    public BigInteger calculatePublicValue() {
         // Returns g^x mod p
         return base.modPow(secret, prime);
     }
 
     // Method to calculate the shared secret key (otherPublic^secret mod p)
-    public static BigInteger calculateSharedSecret(BigInteger otherPublicValue, BigInteger secret, BigInteger prime) {
+    public BigInteger calculateSharedSecret(BigInteger otherPublicValue) {
         // Returns b^x mod p or a^y mod p
         return otherPublicValue.modPow(secret, prime);
     }
+
+    // Static utility methods for direct calculation (if needed)
+    public static BigInteger calculatePublicValue(BigInteger base, BigInteger secret, BigInteger prime) {
+        return base.modPow(secret, prime);
+    }
+
+    public static BigInteger calculateSharedSecret(BigInteger otherPublicValue, BigInteger secret, BigInteger prime) {
+        return otherPublicValue.modPow(secret, prime);
+    }
 }