补充@Kerrek的答案;

身份验证为通用形式(所有员工都可以登录机器)

授权是专用形式(但管理员只能在机器上安装/卸载应用程序)

正如身份验证vs授权所言:

Authentication is the mechanism whereby systems may securely identify their users. Authentication systems provide an answers to the questions: Who is the user? Is the user really who he/she represents himself to be? Authorization, by contrast, is the mechanism by which a system determines what level of access a particular authenticated user should have to secured resources controlled by the system. For example, a database management system might be designed so as to provide certain specified individuals with the ability to retrieve information from a database but not the ability to change data stored in the datbase, while giving other individuals the ability to change data. Authorization systems provide answers to the questions: Is user X authorized to access resource R? Is user X authorized to perform operation P? Is user X authorized to perform operation P on resource R?

参见:

Wikipedia上的身份验证与授权

认证是验证实体身份的过程。例如

Webserver每次都要求用户输入登录名/密码，以验证创建该帐户的用户是否是现在正在访问该帐户的用户。

授权是允许每个实体获得所需数量的服务/资源的过程。例如

On blogging site (eg. medium.com) users can create an account and write a post and publish. And users can read all posts published by others as well. Here the blogging server first authenticates the user with the user login credentials (login/password) and then it authorizes to read all others post and write/modify the post only created by the user. Here authorization is used by the server to limit which all post each user can modify. Users can create a free google account by which google server provides free services like mail, calendar, chat, drives etc. But the storage provided for all these services to free users are 15GB (as of now). User can pay a monthly or annual fee to google server to increase the storage space. Here google server authorizes every authenticated user to limit the amount of resource usage.

在当今的互联网中，授权被广泛用于对客户端施加访问限制。

身份验证是验证所宣布的身份的过程。

例如,用户名/密码

通常接下来是授权，也就是批准你可以这样做或那样做。

如权限

认证是识别有效用户的过程。

授权是验证用户访问级别的过程。

应用程序示例 用户A、用户B均为库存应用的认证用户。 两个用户都可以进入股票，但B对发行项目有更多的授权权力。

身份验证是确定某人确实是他们所声称的那个人的过程。 授权是指决定谁可以做什么的规则。例如，亚当可能被授权创建和删除数据库， 而Usama只被授权阅读。

这两个概念是完全正交和独立的，但它们都是安全设计的核心，如果其中任何一个概念都不正确，就会导致妥协。

就web应用程序而言，简单地说，身份验证是指你检查登录凭证，看看你是否识别出用户已登录，而授权是指你在访问控制中查看是否允许用户查看、编辑、删除或创建内容。