cipher.getAuthTag()

• 返回值：<Buffer> 当使用认证加密模式（当前支持 GCM、CCM、OCB 和 chacha20-poly1305）时，cipher.getAuthTag() 方法返回一个 Buffer，其中包含从给定数据计算出的_认证标签_。

cipher.getAuthTag() 方法应该只在使用 cipher.final() 方法完成加密后调用。

🌐 The cipher.getAuthTag() method should only be called after encryption has been completed using the cipher.final() method.

如果在创建 cipher 实例时设置了 authTagLength 选项，该函数将返回正好 authTagLength 字节的数据。

🌐 If the authTagLength option was set during the cipher instance's creation, this function will return exactly authTagLength bytes.