diff --git a/Makefile b/Makefile
index f816daa..75b17aa 100644
--- a/Makefile
+++ b/Makefile
@@ -1,16 +1,18 @@
+FLAGS = -Wall -Wextra
+
 all: clean build_test build_debug build_profile build_release
 
 build_test:
-	g++ -g -pthread ./src/AES.cpp ./tests/tests.cpp /usr/lib/libgtest.a -o bin/test
+	g++ $(FLAGS) -g -pthread ./src/AES.cpp ./tests/tests.cpp /usr/lib/libgtest.a -o bin/test
 
 build_debug:
-	g++ -g ./src/AES.cpp ./dev/main.cpp -o bin/debug
+	g++ $(FLAGS) -g ./src/AES.cpp ./dev/main.cpp -o bin/debug
 
 build_profile:
-	g++ -pg ./src/AES.cpp ./dev/main.cpp -o bin/profile
+	g++ $(FLAGS) -pg ./src/AES.cpp ./dev/main.cpp -o bin/profile
 
 build_release:
-	g++ -O2 ./src/AES.cpp ./dev/main.cpp -o bin/release
+	g++ $(FLAGS) -O2 ./src/AES.cpp ./dev/main.cpp -o bin/release
 
 clean:
 	rm -rf bin 
diff --git a/dev/main.cpp b/dev/main.cpp
index 970c2bf..45603a1 100644
--- a/dev/main.cpp
+++ b/dev/main.cpp
@@ -1,7 +1,7 @@
 #include <iostream>
 #include "../src/AES.h"
 
-int main(int argc, char *argv[])
+int main()
 {
   cout << "Aes dev" << endl;
   return 0;
diff --git a/src/AES.cpp b/src/AES.cpp
index 0e34eb9..346a02d 100644
--- a/src/AES.cpp
+++ b/src/AES.cpp
@@ -274,10 +274,8 @@ void AES::SubBytes(unsigned char **state)
 
 void AES::ShiftRow(unsigned char **state, int i, int n)    // shift row i on n positions
 {
-  unsigned char t;
-  int k, j, index;
   unsigned char *tmp = new unsigned char[Nb];
-  for (j = 0; j < Nb; j++) {
+  for (int j = 0; j < Nb; j++) {
     tmp[j] = state[i][(j + n) % Nb];
   }
   memcpy(state[i], tmp, Nb * sizeof(unsigned char));
@@ -521,7 +519,7 @@ void AES::XorBlocks(unsigned char *a, unsigned char * b, unsigned char *c, unsig
 
 void AES::printHexArray (unsigned char a[], unsigned int n)
 {
-	for (int i = 0; i < n; i++) {
+	for (unsigned int i = 0; i < n; i++) {
 	  printf("%02x ", a[i]);
 	}
 }