diff --git a/src/parseArguments.c b/src/parseArguments.c
index 1597ee6..019d764 100644
--- a/src/parseArguments.c
+++ b/src/parseArguments.c
@@ -1,6 +1,7 @@
 #include <getopt.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include "decrypt.h"
 #include "errorAndExit.h"
@@ -49,13 +50,26 @@ struct arguments parseArguments(int argc, char *argv[]) {
         state.fileSize = atol(optarg);
         hasSize = true;
         break;
-      case 'k': { //decryption keys
-        //TODO: parse from optarg
-        uint32_t key0 = atoi(argv[8]);
-        uint32_t key1 = atoi(argv[9]);
-        uint32_t key2 = atoi(argv[10]);
+      case 'k': { //decryption keys (12345,12345,12345)
+        //Split argument by comma into three integers
+        char* token = strtok(optarg, ",");
+        uint32_t keys[3] = { 0UL, 0UL, 0UL };
+        int index = 0;
+        while (token != NULL) {
+          if (index > 2) {
+            fprintf(stderr, "Too many decryption keys specified with --keys; only 3 are allowed.\n");
+            errorAndExit();
+          }
+          keys[index] = atoi(token);
+          index += 1;
+          token = strtok(NULL, ",");
+        }
+        if (index < 3) {
+          fprintf(stderr, "Not enough decryption keys specified with --keys; 3 are required but only found %i.\n", index);
+          errorAndExit();
+        }
         //Initialize decryption (pass decryption keys)
-        initDecryptor(key0, key1, key2);
+        initDecryptor(keys[0], keys[1], keys[2]);
         state.isEncrypted = true;
         break;
       }