diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 709f6cf..09379a0 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -502,6 +502,13 @@
 #define MBEDTLS_CIPHER_MODE_CBC
 
 /**
+ * \def MBEDTLS_CIPHER_MODE_XEX
+ *
+ * Enable Xor-encrypt-xor mode (XEX) for symmetric ciphers.
+ */
+#define MBEDTLS_CIPHER_MODE_XEX
+
+/**
  * \def MBEDTLS_CIPHER_MODE_OFB
  *
  * Enable Output Feedback mode (OFB) for symmetric ciphers.