PHP的openssl_sign与Dart等效吗？

Question

我一定缺少搜索此内容的东西。似乎无法在Dart中找到PHP的openssl_sign方法的等效项，例如以下操作：

<?php
// $data is assumed to contain the data to be signed

// fetch private key from file and ready it
$pkeyid = openssl_pkey_get_private("file://src/openssl-0.9.6/demos/sign/key.pem");

// compute signature
openssl_sign($data, $signature, $pkeyid);

谢谢。