diff --git a/include/polarssl/rsa.h b/include/polarssl/rsa.h
index 26dddbc..295a2db 100644
--- a/include/polarssl/rsa.h
+++ b/include/polarssl/rsa.h
@@ -28,14 +28,14 @@
 /*
  * RSA Error codes
  */
-#define POLARSSL_ERR_RSA_BAD_INPUT_DATA                    0x0400
-#define POLARSSL_ERR_RSA_INVALID_PADDING                   0x0410
-#define POLARSSL_ERR_RSA_KEY_GEN_FAILED                    0x0420
-#define POLARSSL_ERR_RSA_KEY_CHECK_FAILED                  0x0430
-#define POLARSSL_ERR_RSA_PUBLIC_FAILED                     0x0440
-#define POLARSSL_ERR_RSA_PRIVATE_FAILED                    0x0450
-#define POLARSSL_ERR_RSA_VERIFY_FAILED                     0x0460
-#define POLARSSL_ERR_RSA_OUTPUT_TOO_LARGE                  0x0470
+#define POLARSSL_ERR_RSA_BAD_INPUT_DATA                    -0x0400
+#define POLARSSL_ERR_RSA_INVALID_PADDING                   -0x0410
+#define POLARSSL_ERR_RSA_KEY_GEN_FAILED                    -0x0420
+#define POLARSSL_ERR_RSA_KEY_CHECK_FAILED                  -0x0430
+#define POLARSSL_ERR_RSA_PUBLIC_FAILED                     -0x0440
+#define POLARSSL_ERR_RSA_PRIVATE_FAILED                    -0x0450
+#define POLARSSL_ERR_RSA_VERIFY_FAILED                     -0x0460
+#define POLARSSL_ERR_RSA_OUTPUT_TOO_LARGE                  -0x0470
 
 /*
  * PKCS#1 constants