diff --git a/armsrc/desfire_key.c b/armsrc/desfire_key.c
index d9db46efa..3bab33f50 100644
--- a/armsrc/desfire_key.c
+++ b/armsrc/desfire_key.c
@@ -147,9 +147,9 @@ void Desfire_session_key_new(const uint8_t rnda[], const uint8_t rndb[], desfire
         case T_2K3DES:
             memcpy(buffer, rnda, 4);
             memcpy(buffer + 4, rndb, 4);
-            memcpy(buffer + 8, rnda + 4, 4);
-            memcpy(buffer + 12, rndb + 4, 4);
-            Desfire_3des_key_new_with_version(buffer, key);
+            memcpy(buffer + 8, rnda+4, 4);
+            memcpy(buffer + 12, rndb+4, 4);
+            Desfire_2k3des_key_new_with_version(buffer, key);
             break;
         case T_3K3DES:
             memcpy(buffer, rnda, 4);