diff --git a/library/pk.c b/library/pk.c
index 06021e2..275d34b 100644
--- a/library/pk.c
+++ b/library/pk.c
@@ -500,7 +500,10 @@
 /*
  * Check public-private key pair
  */
-int mbedtls_pk_check_pair( const mbedtls_pk_context *pub, const mbedtls_pk_context *prv )
+int mbedtls_pk_check_pair( const mbedtls_pk_context *pub,
+                           const mbedtls_pk_context *prv,
+                           int (*f_rng)(void *, unsigned char *, size_t),
+                           void *p_rng )
 {
     PK_VALIDATE_RET( pub != NULL );
     PK_VALIDATE_RET( prv != NULL );
@@ -511,6 +514,9 @@
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
     }
 
+    if( f_rng == NULL )
+        return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
+
     if( prv->pk_info->check_pair_func == NULL )
         return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
 
@@ -525,7 +531,7 @@
             return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
     }
 
-    return( prv->pk_info->check_pair_func( pub->pk_ctx, prv->pk_ctx ) );
+    return( prv->pk_info->check_pair_func( pub->pk_ctx, prv->pk_ctx, f_rng, p_rng ) );
 }
 
 /*