testing

Diffie-Hellman-Key-Exchange/README.md

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+# Diffie-Hellman Key Exchange
+
+## Description
+This project implements a basic version of the Diffie-Hellman key exchange algorithm, allowing two parties (Alice and Bob) to agree on a shared secret over an insecure channel.
+
+## How to Build
+1. Navigate to the `build` directory.
+2. Run `make` to compile the project.
+
+## How to Run
+1. After building, run the `diffie_hellman` executable using `./diffie_hellman`.
+
+## How to Clean
+- Run `make clean` to remove all compiled files.

Diffie-Hellman-Key-Exchange/build/Makefile

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+# Variables
+CC = gcc
+CFLAGS = -I../include -Wall -Wextra
+OBJDIR = ../obj
+SRCDIR = ../src
+BINDIR = ../build
+
+# Source files
+SOURCES = $(SRCDIR)/main.c $(SRCDIR)/diffie_hellman.c
+OBJECTS = $(OBJDIR)/main.o $(OBJDIR)/diffie_hellman.o
+
+# Build target
+TARGET = diffie_hellman
+
+# Rules
+all: $(BINDIR)/$(TARGET)
+
+$(BINDIR)/$(TARGET): $(OBJECTS)
+	$(CC) $(OBJECTS) -o $(BINDIR)/$(TARGET)
+
+$(OBJDIR)/%.o: $(SRCDIR)/%.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+clean:
+	rm -f $(OBJDIR)/*.o $(BINDIR)/$(TARGET)
+
+.PHONY: all clean

Diffie-Hellman-Key-Exchange/include/diffie_hellman.h

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+#ifndef DIFFIE_HELLMAN_H
+#define DIFFIE_HELLMAN_H
+
+unsigned long long generate_public_key(unsigned long long base, unsigned long long private_key, unsigned long long prime);
+unsigned long long generate_shared_secret(unsigned long long received_public_key, unsigned long long private_key, unsigned long long prime);
+
+#endif // DIFFIE_HELLMAN_H

Diffie-Hellman-Key-Exchange/src/diffie_hellman.c

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+#include "diffie_hellman.h"
+#include <stdio.h>
+#include <math.h>
+
+// Generate the public key: A = g^a mod p
+unsigned long long generate_public_key(unsigned long long base, unsigned long long private_key, unsigned long long prime) {
+    unsigned long long result = 1;
+    for (unsigned long long i = 0; i < private_key; i++) {
+        result = (result * base) % prime;
+    }
+    return result;
+}
+
+// Generate the shared secret: s = B^a mod p
+unsigned long long generate_shared_secret(unsigned long long received_public_key, unsigned long long private_key, unsigned long long prime) {
+    unsigned long long result = 1;
+    for (unsigned long long i = 0; i < private_key; i++) {
+        result = (result * received_public_key) % prime;
+    }
+    return result;
+}

Diffie-Hellman-Key-Exchange/src/main.c

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+#include "diffie_hellman.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+int main() {
+    // Publicly agreed upon base (g) and prime (p)
+    unsigned long long base = 5;
+    unsigned long long prime = 23;
+
+    // Private keys chosen by Alice and Bob (should be random in practice)
+    unsigned long long alice_private_key, bob_private_key;
+    srand(time(NULL));
+    alice_private_key = rand() % (prime - 1) + 1;  // Random private key for Alice
+    bob_private_key = rand() % (prime - 1) + 1;    // Random private key for Bob
+
+    printf("Alice's private key: %llu\n", alice_private_key);
+    printf("Bob's private key: %llu\n", bob_private_key);
+
+    // Generate public keys
+    unsigned long long alice_public_key = generate_public_key(base, alice_private_key, prime);
+    unsigned long long bob_public_key = generate_public_key(base, bob_private_key, prime);
+
+    printf("Alice's public key: %llu\n", alice_public_key);
+    printf("Bob's public key: %llu\n", bob_public_key);
+
+    // Exchange public keys and generate shared secrets
+    unsigned long long alice_shared_secret = generate_shared_secret(bob_public_key, alice_private_key, prime);
+    unsigned long long bob_shared_secret = generate_shared_secret(alice_public_key, bob_private_key, prime);
+
+    printf("Alice's shared secret: %llu\n", alice_shared_secret);
+    printf("Bob's shared secret: %llu\n", bob_shared_secret);
+
+    // Verify if shared secrets match
+    if (alice_shared_secret == bob_shared_secret) {
+        printf("Key exchange successful! Shared secret: %llu\n", alice_shared_secret);
+    } else {
+        printf("Key exchange failed.\n");
+    }
+
+    return 0;
+}