diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index e14fc74d7..4974f4774 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -671,6 +671,13 @@
 #define MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN
 #define MBEDTLS_CIPHER_PADDING_ZEROS
 
+/** \def MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
+ *
+ * Uncomment this macro to use a 128-bit key in the CTR_DRBG module.
+ * By default, CTR_DRBG uses a 256-bit key.
+ */
+//#define MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
+
 /**
  * \def MBEDTLS_ECP_DP_SECP192R1_ENABLED
  *
@@ -1295,7 +1302,7 @@
  *
  * Enable the CTR_DRBG AES-based random generator.
  * The CTR_DRBG generator uses AES-256 by default.
- * To use AES-128 instead, enable MBEDTLS_CTR_DRBG_USE_128_BIT_KEY below.
+ * To use AES-128 instead, enable \c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY above.
  *
  * Module:  library/ctr_drbg.c
  * Caller:
@@ -1971,7 +1978,6 @@
 //#define MBEDTLS_CTR_DRBG_MAX_INPUT                256 /**< Maximum number of additional input bytes */
 //#define MBEDTLS_CTR_DRBG_MAX_REQUEST             1024 /**< Maximum number of requested bytes per call */
 //#define MBEDTLS_CTR_DRBG_MAX_SEED_INPUT           384 /**< Maximum size of (re)seed buffer */
-//#define MBEDTLS_CTR_DRBG_USE_128_BIT_KEY              /**< Use 128-bit key for CTR_DRBG - may reduce security (see ctr_drbg.h) */
 
 /* HMAC_DRBG options */
 //#define MBEDTLS_HMAC_DRBG_RESEED_INTERVAL   10000 /**< Interval before reseed is performed by default */
diff --git a/library/version_features.c b/library/version_features.c
index 5404d79f0..a91723fcf 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -300,6 +300,9 @@ static const char * const features[] = {
 #if defined(MBEDTLS_CIPHER_PADDING_ZEROS)
     "MBEDTLS_CIPHER_PADDING_ZEROS",
 #endif /* MBEDTLS_CIPHER_PADDING_ZEROS */
+#if defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
+    "MBEDTLS_CTR_DRBG_USE_128_BIT_KEY",
+#endif /* MBEDTLS_CTR_DRBG_USE_128_BIT_KEY */
 #if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED)
     "MBEDTLS_ECP_DP_SECP192R1_ENABLED",
 #endif /* MBEDTLS_ECP_DP_SECP192R1_ENABLED */
diff --git a/programs/test/query_config.c b/programs/test/query_config.c
index da3dfb080..1832b2c88 100644
--- a/programs/test/query_config.c
+++ b/programs/test/query_config.c
@@ -828,6 +828,14 @@ int query_config( const char *config )
     }
 #endif /* MBEDTLS_CIPHER_PADDING_ZEROS */
 
+#if defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
+    if( strcmp( "MBEDTLS_CTR_DRBG_USE_128_BIT_KEY", config ) == 0 )
+    {
+        MACRO_EXPANSION_TO_STR( MBEDTLS_CTR_DRBG_USE_128_BIT_KEY );
+        return( 0 );
+    }
+#endif /* MBEDTLS_CTR_DRBG_USE_128_BIT_KEY */
+
 #if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED)
     if( strcmp( "MBEDTLS_ECP_DP_SECP192R1_ENABLED", config ) == 0 )
     {
@@ -1676,14 +1684,6 @@ int query_config( const char *config )
     }
 #endif /* MBEDTLS_CTR_DRBG_MAX_SEED_INPUT */
 
-#if defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
-    if( strcmp( "MBEDTLS_CTR_DRBG_USE_128_BIT_KEY", config ) == 0 )
-    {
-        MACRO_EXPANSION_TO_STR( MBEDTLS_CTR_DRBG_USE_128_BIT_KEY );
-        return( 0 );
-    }
-#endif /* MBEDTLS_CTR_DRBG_USE_128_BIT_KEY */
-
 #if defined(MBEDTLS_HMAC_DRBG_RESEED_INTERVAL)
     if( strcmp( "MBEDTLS_HMAC_DRBG_RESEED_INTERVAL", config ) == 0 )
     {