diff --git a/include/polarssl/dhm.h b/include/polarssl/dhm.h
index 219989e..5975681 100644
--- a/include/polarssl/dhm.h
+++ b/include/polarssl/dhm.h
@@ -24,12 +24,12 @@
 
 #include "polarssl/bignum.h"
 
-#define POLARSSL_ERR_DHM_BAD_INPUT_DATA                    -0x0480
-#define POLARSSL_ERR_DHM_READ_PARAMS_FAILED                -0x0490
-#define POLARSSL_ERR_DHM_MAKE_PARAMS_FAILED                -0x04A0
-#define POLARSSL_ERR_DHM_READ_PUBLIC_FAILED                -0x04B0
-#define POLARSSL_ERR_DHM_MAKE_PUBLIC_FAILED                -0x04C0
-#define POLARSSL_ERR_DHM_CALC_SECRET_FAILED                -0x04D0
+#define POLARSSL_ERR_DHM_BAD_INPUT_DATA                    0x0480
+#define POLARSSL_ERR_DHM_READ_PARAMS_FAILED                0x0490
+#define POLARSSL_ERR_DHM_MAKE_PARAMS_FAILED                0x04A0
+#define POLARSSL_ERR_DHM_READ_PUBLIC_FAILED                0x04B0
+#define POLARSSL_ERR_DHM_MAKE_PUBLIC_FAILED                0x04C0
+#define POLARSSL_ERR_DHM_CALC_SECRET_FAILED                0x04D0
 
 typedef struct
 {