diff --git a/library/hmac_drbg.c b/library/hmac_drbg.c
index c9c541d..b51e9b1 100644
--- a/library/hmac_drbg.c
+++ b/library/hmac_drbg.c
@@ -70,7 +70,8 @@
                                   const unsigned char *additional,
                                   size_t add_len )
 {
-    size_t md_len = mbedtls_md_get_size( ctx->md_ctx.md_info );
+    size_t md_len = mbedtls_md_get_size(
+        mbedtls_md_get_handle( &ctx->md_ctx ) );
     unsigned char rounds = ( additional != NULL && add_len != 0 ) ? 2 : 1;
     unsigned char sep[1];
     unsigned char K[MBEDTLS_MD_MAX_SIZE];
@@ -329,7 +330,8 @@
 {
     int ret;
     mbedtls_hmac_drbg_context *ctx = (mbedtls_hmac_drbg_context *) p_rng;
-    size_t md_len = mbedtls_md_get_size( ctx->md_ctx.md_info );
+    size_t md_len = mbedtls_md_get_size(
+        mbedtls_md_get_handle( &ctx->md_ctx ) );
     size_t left = out_len;
     unsigned char *out = output;