diff --git a/Implementierung/Makefile b/Implementierung/Makefile
index d6b448b..ac2efc2 100644
--- a/Implementierung/Makefile
+++ b/Implementierung/Makefile
@@ -1,14 +1,14 @@
 FLAGS=-O3 -std=c11 -g -Wall -Wextra -no-pie
 
 .PHONY: all
-	all: main
-main: main.c toupper.S
+all: main
+main: main.c
 		$(CC) $(CFLAGS) -o $@ $^
 
 .PHONY: clean
-	clean:
-		rm -f main
+clean:
+	rm -f main
 
 .PHONY: run
-	run:
-		./main
+run:
+	./main
diff --git a/Implementierung/main b/Implementierung/main
new file mode 100755
index 0000000..c930f60
Binary files /dev/null and b/Implementierung/main differ
diff --git a/Implementierung/main.c b/Implementierung/main.c
index 0eafbf0..6b751f0 100644
--- a/Implementierung/main.c
+++ b/Implementierung/main.c
@@ -1,3 +1,151 @@
-int main(int argc, char* argv) {
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+#include <xmmintrin.h>
+#include <errno.h>
+#include <immintrin.h>
+#include <stdint.h>
+#include <getopt.h>
+
+// The file "testfile" should lead to this hash: fc982e558db259f298b43cd4c1241c66
+
+void md2_checksum(size_t len, uint8_t* buf) {
+
+}
+
+void md2_hash(size_t len, const uint8_t buf[len], uint8_t out[16]) {
+
+}
+
+static uint8_t* read_file(const char* path) {
+    // Read the contents of the file specified by path into a heap-allocated
+    // buffer and return a pointer to that buffer.
+    FILE* f = fopen(path, "r");
+    if(f == NULL) {
+        printf("Fopen error: %d\n", errno);
+        fclose(f);
+        return NULL;
+    }
+
+    struct stat statOfFile;
+    int status = fstat(fileno(f), &statOfFile);
+    if(status == -1) {
+        printf("Fstat error: %d\n", errno);
+        fclose(f);
+        return NULL;
+    };
+
+    if((statOfFile.st_mode & S_IFMT) != S_IFREG){
+        printf("File is not a regular file!\n");
+        fclose(f);
+        return NULL;
+    }
+
+    uint8_t* data = malloc(statOfFile.st_size);
+
+    size_t bytesRead = fread(data, statOfFile.st_blksize, statOfFile.st_blocks, f);
+    // Or: size_t bytesRead = fread(data, sizeof(char), statOfFile.st_size, f);
+    if(bytesRead != 0 && !feof(f)) {
+        printf("Error reading file!\n");
+        fclose(f);
+        return NULL;
+    }
+
+    fclose(f);
+
+    return data;
+}
+
+int stringToInt(char* string) {
+    char* leftover = "";
+    errno = 0;
+    int x = strtold(string, &leftover);
+    if(*leftover != '\0' || leftover == string) {
+        errno = EINVAL;
+        return -1;
+    }
+    if(errno == ERANGE) {
+        printf("Number is too large or too small!\n");
+        errno = EINVAL;
+        return -1;
+    }
+    errno = 0;
+    return x;
+}
+
+void help(char* progname) {
+    fprintf(stderr, "usage: %s [-V implementation] [-B [repetitons]] [-h] [--help] file\n", progname);
+}
+
+int main(int argc, char** argv) {
+     
+    int opt;
+    int implementationTosUse = 0;
+    int doBenchmark = 0;
+    int benchmarkingCycles = 1;
+
+    while (1) {
+
+        static struct option longOptions[] =
+        {
+            /* These options set a flag. */
+            {"help", no_argument, 0, 'h'},
+            {0, 0, 0, 0}
+        };
+        int longOptionIndex = 0;
+
+        opt = getopt_long(argc, argv, "V:B::h", longOptions, &longOptionIndex);
+
+        if(-1 == opt)
+            break;
+
+        switch (opt) {
+        case 'B': 
+            doBenchmark = 1;
+            if(optarg != NULL) {
+                benchmarkingCycles = stringToInt(optarg);
+                if(errno == 0) break;
+                fprintf(stderr, "%s: invalid argument, has to be int -- 'B' got '%s'\n", argv[0], optarg); 
+                help(argv[0]);
+                return EXIT_FAILURE;
+            }
+            break;
+        case 'V': 
+            implementationTosUse = stringToInt(optarg);
+            if(errno == 0) break;
+            fprintf(stderr, "%s: invalid argument, has to be int -- 'V' got '%s'\n", argv[0], optarg);
+            help(argv[0]);
+            return EXIT_FAILURE;
+
+        case 'h':
+            help(argv[0]);
+            return EXIT_SUCCESS;
+
+        default:
+            help(argv[0]);
+            return EXIT_FAILURE;
+        }
+    }
+
+    char* filename = "";
+
+    if(argc > optind) {
+        filename = argv[optind];
+    }
+    else {
+        fprintf(stderr, "%s: missing poisional argument -- 'file'\n", argv[0]);
+        help(argv[0]);
+        return EXIT_FAILURE;
+    }
+
+    printf("Hashing file: %s\nUsing implementation: %d, doing benchmark: %d, benchmark cycles: %d\n", filename, implementationTosUse, doBenchmark, benchmarkingCycles);
+
     return 0;
 }
diff --git a/Implementierung/testfile b/Implementierung/testfile
new file mode 100644
index 0000000..d72e1a3
Binary files /dev/null and b/Implementierung/testfile differ