diff --git a/sha.c b/sha.c
index eff318b..bc6bfdb 100644
--- a/sha.c
+++ b/sha.c
@@ -753,7 +753,10 @@ void usage(void)
 int main(int argc, char *argv[])
 {
     static uint8_t key[16] = "aixiao.me";
+    int key_l = 0;
     char sh_file[1024];
+
+    
     int opt;
     char optstrs[] = ":k:f:h?";
     while (-1 != (opt = getopt(argc, argv, optstrs))) {
@@ -764,7 +767,6 @@ int main(int argc, char *argv[])
         case 'f':
             strcpy((char *)sh_file, optarg);
             break;
-        
         case ':':
             //printf("\nMissing argument after: -%c\n", optopt);
             usage();
@@ -777,11 +779,16 @@ int main(int argc, char *argv[])
         }
     }
     
-    if (strlen((char *)key) < 8) {
-        printf("Key must be at least 8 digits!\n");
+    key_l = strlen((char *)key);
+    //printf("%d\n", key_l);
+    
+    
+    if (key_l < 8 || key_l > 15) {
+        printf("The key must be 8-15 digits!\n");
         exit(1);
     }
     
+    
     open_file(sh_file);
     
     struct AES_ctx ctx;