diff --git a/library/rsa.c b/library/rsa.c
index e915e4f..d3ab4ed 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -473,7 +473,7 @@
     memset( mask, 0, POLARSSL_MD_MAX_SIZE );
     memset( counter, 0, 4 );
 
-    hlen = md_ctx->md_info->size;
+    hlen = md_get_size( md_ctx->md_info );
 
     // Generate and apply dbMask
     //