diff --git a/Implementierung/src/io.c b/Implementierung/src/io.c
index 048aee7..942f235 100644
--- a/Implementierung/src/io.c
+++ b/Implementierung/src/io.c
@@ -36,7 +36,7 @@ uint8_t* read_file(const char* path, size_t* size) {
   uint8_t* data = malloc(statOfFile.st_size);
   if (data == NULL) {
     printf("Failure: malloc returns NULL");
-    return -1;
+    return EXIT_FAILURE;
   }
 
   size_t bytesRead =
diff --git a/Implementierung/src/md2_impls/md2_0.c b/Implementierung/src/md2_impls/md2_0.c
index c344325..941b352 100644
--- a/Implementierung/src/md2_impls/md2_0.c
+++ b/Implementierung/src/md2_impls/md2_0.c
@@ -27,7 +27,7 @@ void md2_hash_0(size_t len, const uint8_t buf[len], uint8_t out[16]) {
   uint8_t* newBuf = calloc(len + 16, sizeof(uint8_t));
   if (newBuf == NULL) {
     printf("Failure: calloc returns NULL");
-    return -1;
+    return EXIT_FAILURE;
   }
   memcpy(newBuf, buf, len - paddingNeeded);
 
@@ -50,7 +50,7 @@ void md2_hash_0(size_t len, const uint8_t buf[len], uint8_t out[16]) {
   uint8_t* messageDigestBuf = calloc(48, sizeof(uint8_t));
   if (messageDigestBuf == NULL) {
     printf("Failure: calloc returns NULL");
-    return -1;
+    return EXIT_FAILURE;
   }
 
 
diff --git a/Implementierung/src/md2_impls/md2_1.c b/Implementierung/src/md2_impls/md2_1.c
index ff2f1ff..d4fb80b 100644
--- a/Implementierung/src/md2_impls/md2_1.c
+++ b/Implementierung/src/md2_impls/md2_1.c
@@ -48,7 +48,7 @@ void md2_hash_1(size_t len, const uint8_t buf[len], uint8_t out[16])
   uint8_t* newBuf = aligned_alloc(16, sizeof(uint8_t)*(len + 16));
   if (newBuf == NULL) {
     printf("Failure: aligned_alloc returns NULL");
-    return -1;
+    return EXIT_FAILURE;
   }
 
   for(size_t i = 0; i < 16; i++) {
@@ -66,7 +66,7 @@ void md2_hash_1(size_t len, const uint8_t buf[len], uint8_t out[16])
   uint8_t *messageDigestBuf = aligned_alloc(16, sizeof(uint8_t) * 48);
   if (messageDigestBuf == NULL) {
     printf("Failure: aligned_alloc returns NULL");
-    return -1;
+    return EXIT_FAILURE;
   }
 
   for (size_t i = 0; i < 48; i++) {
diff --git a/Implementierung/src/md2_impls/md2_2.c b/Implementierung/src/md2_impls/md2_2.c
index b0955ba..5253ce7 100644
--- a/Implementierung/src/md2_impls/md2_2.c
+++ b/Implementierung/src/md2_impls/md2_2.c
@@ -52,7 +52,7 @@ void md2_hash_2(size_t len, const uint8_t buf[len], uint8_t out[16]) {
   uint8_t* messageDigestBuf = calloc(48, sizeof(uint8_t));
   if (messageDigestBuf == NULL) {
     printf("Failure: calloc returns NULL");
-    return -1;
+    return EXIT_FAILURE;
   }
 
   // === step 4 ===
@@ -60,13 +60,13 @@ void md2_hash_2(size_t len, const uint8_t buf[len], uint8_t out[16]) {
   uint8_t* checksum = calloc(16, sizeof(uint8_t));
   if (checksum == NULL) {
     printf("Failure: calloc returns NULL");
-    return -1;
+    return EXIT_FAILURE;
   }
 
   uint8_t* data = malloc(16);
   if (data == NULL) {
     printf("Failure: malloc returns NULL");
-    return -1;
+    return EXIT_FAILURE;
   }
   size_t bytes_left_to_read = file_stat.st_size;
   size_t bytes_left_to_process = 0;