diff --git a/library/lms.c b/library/lms.c
index e7ae5081c2..adba195826 100644
--- a/library/lms.c
+++ b/library/lms.c
@@ -588,7 +588,7 @@ int mbedtls_lms_generate_private_key( mbedtls_lms_private_t *ctx,
         goto exit;
     }
 
-    ctx->ots_private_keys = mbedtls_calloc( ( size_t )MERKLE_TREE_LEAF_NODE_AM(ctx->params.type),
+    ctx->ots_private_keys = mbedtls_calloc( MERKLE_TREE_LEAF_NODE_AM(ctx->params.type),
                                             sizeof( *ctx->ots_private_keys ) );
     if( ctx->ots_private_keys == NULL )
     {
@@ -596,7 +596,7 @@ int mbedtls_lms_generate_private_key( mbedtls_lms_private_t *ctx,
         goto exit;
     }
 
-    ctx->ots_public_keys = mbedtls_calloc( ( size_t )MERKLE_TREE_LEAF_NODE_AM(ctx->params.type),
+    ctx->ots_public_keys = mbedtls_calloc( MERKLE_TREE_LEAF_NODE_AM(ctx->params.type),
                                            sizeof( *ctx->ots_public_keys ) );
     if( ctx->ots_public_keys == NULL )
     {