使用 JWT 在 Asp.net Web API 上实现身份验证 [英] Using JWT to implement Authentication on Asp.net web API

问题描述

我一直在阅读有关 JWT 的文章.

I have been reading about JWT.

但从我的阅读来看，它不是一种身份验证机制，而更像是身份验证机制中的一个关键组件.

But from what I read it is not an authentication mechanism but more like a crucial component in a Authentication mechanism.

我目前已经实现了一个可行的解决方案，但它只是尝试 JWT 并看看它是如何工作的.但我现在所追求的是如何利用它.根据我的经验，它基本上只是一种加密机制，可为您提供唯一的加密密钥.您还可以将信息放入此令牌中.

I have currently implemented a solution which works, but it was just to try out JWT and see how it works. But what I am after now is how one should make use of it. From my experience of it its basically just an encryption mechanism that gives you a unique encrypted key. You are also able to put information inside of this token.

我想在 ASP.NET web api 2 上实现它，以供移动应用程序使用.

I am wanting to implement it in terms on a ASP.NET web api 2 to be consumed by a mobile application.

所以第 1 步:

1. app => 服务器:登录(用户、密码)
2. 服务器 => 应用程序:登录 OK，这是您的 JWT
3. app => server : 获取我的个人资料(通过请求发送 JWT)然后服务器解密 JWT 并确定请求的身份.

现在这只是我的理解，看我可能走错了路.

Now this is just my understanding of it, Look I could be on the totally wrong path.

JWT 的理想是让您不必对每个请求进行身份验证吗?我只需验证用户凭据一次(在初始登录时)，然后在服务器可以简单地使用 JWT 并且不必在数据库中查找用户密码和用户之后?

Is the Ideal of JWT so that you dont have to authenticate on every request? I just authenticate the users credentials once (on the initial login) and there on after the server can simply use JWT and no have to lookup the users pw and user in the DB?

我只想使用 JWT 来识别用户是谁.然后，在我对它们进行身份验证后，我将进行授权.据我所知，新的 MVC 以及身份验证和授权存在很大的混淆.

I just want to use the JWT to Identity who the user is. I will then authorize then after i have authenticated them. As I know there is a big confused with the new MVC and Authentication and Authorization.

所以我的问题归结为.

如何使用 JWT 安全有效地实现身份验证机制?我不想只是咳出一些似乎有效的东西，而且对安全隐患没有任何想法.我确信有一个来源可能设计了一个适合我要求的安全机制.

How can I safely and effectively Implement a Authentication Mechanism Using JWT? I don't want to just cough something up that seems to work and not have any Idea of the security implications. I am sure that there exists a source some where that has possibly designed a secure mechanism that would suit my requirements.

我的要求是:

• 每次会话只需要检查一次用户凭据的数据库吗?由于使用 bcrypt 使用大量资源来比较密码.
• 必须能够从他们的请求中识别用户.(即他们是谁，userId 就足够了)并且最好不要访问数据库
• 对于服务器端处理请求的资源，应尽可能降低开销.
• 如果入侵者必须复制设备先前的请求，那么他应该无法访问真实用户数据.(显然)

谢谢

推荐答案

你对 JWT 的理解不错.但这里有一些更正和一些建议.

Your understanding of JWTs is good. But here are a couple corrections and some recommendations.

• JWT 与身份验证无关.只有当您在创建 JWT 时进行身份验证时，才会点击您的数据库和散列密码.这与 JWT 正交，您可以以任何您喜欢的方式进行操作.我个人喜欢 会员重启，这也有一个使用 JWT 的好例子.
• 理论上，您可以让用户每年输入一次密码，并让 JWT 在一整年都有效.这很可能不是最好的解决方案，如果 JWT 在任何时候被盗，用户资源就会受到损害.

• JWTs have nothing to do with authentication. Hitting your DB and hashing passwords only happens when you authenticate on creation of the JWT. This is orthogonal to JWTs and you can do that in any way you like. I personally like Membership Reboot, which also has a good example of using JWTs.
• Theoretically, you could have the user enter a password once a year and have the JWT be valid that entire year. This most likely not the best solution, if the JWT gets stolen at any point the users resources would be compromised.

• 令牌可以但不必加密.加密令牌会增加系统的复杂性和服务器读取 JWT 所需的计算量.如果您要求在令牌静止时没有人能够读取令牌，这可能很重要.
• 令牌始终由发行者进行加密签名，以确保其完整性.这意味着它们不能被用户或第三方篡改.

您的 JWT 可以包含您想要的任何信息.用户名、生日、电子邮件等.您可以使用基于声明的授权来执行此操作.然后，您只需告诉您的提供商使用声明原则中的这些声明创建 JWT.以下代码来自该会员重启示例，它向您展示了这是如何完成的.

Your JWTs can contain any information you want. The users name, birthdate, email, etc. You do this with claims based authorization. You then just tell your provider to make a JWT with these claims from the Claims Principle. The following code is from that Membership Reboot example and it shows you how this is done.

public override Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
{
    var svc = context.OwinContext.Environment.GetUserAccountService<UserAccount>();
    UserAccount user;
    if (svc.Authenticate("users", context.UserName, context.Password, out user))
    {
        var claims = user.GetAllClaims();

        var id = new System.Security.Claims.ClaimsIdentity(claims, "MembershipReboot");
        context.Validated(id);
    }

    return base.GrantResourceOwnerCredentials(context);
}

这使您可以精确控制谁在访问您的资源，而所有这些都不会影响您的处理器密集型身份验证服务.

This allows you to control with precision whom is accessing your resources, all without hitting your processor intensive authentication service.

实现令牌提供程序的一种非常简单的方法是使用 Microsoft 的 OAuth 授权服务器 在您的 WebAPI 项目中.它为您提供了为您的 API 制作 OAuth 服务器所需的基本知识.

A very easy way to implement a Token provider is to use Microsoft's OAuth Authorization Server in your WebAPI project. It give you the bare bones of what you need to make a OAuth server for your API.

您还可以查看 Thinktecture 的 Identity Server，它会给您带来很多好处更容易控制用户.例如，您可以使用身份服务器轻松实现刷新令牌，其中用户经过身份验证一次，然后在一定时间(可能是一个月)内，他们可以继续从身份服务器获取短期 JWT.刷新令牌很好，因为它们可以被撤销，而 JWT 不能.此解决方案的缺点是您需要设置另一台或两台服务器来托管身份服务.

You could also look into Thinktecture's Identity Server which would give you much easier control over users. For instance, you can easily implement refresh tokens with identity server where the user is authenticated once and then for a certain amount of time (maybe a month) they can continue getting short lived JWTs from the Identity Server. The refresh tokens are good because they can be revoked, whereas JWTs cannot. The downside of this solution is that you need to set up another server or two to host the Identity service.

要处理您的最后一点，即入侵者不应复制最后一个请求以访问资源，您必须至少使用 SSL. 这将保护令牌在运输中.

To deal with your last point, that an intruder should not be able to copy the last request to get access to a resource, you must use SSL at a bare minimum. This will protect the token in transport.

如果您要保护一些极其敏感的东西，您应该将令牌的生命周期保持在一个非常短的时间窗口内.如果您保护的是不那么敏感的东西，您可以延长使用寿命.如果令牌有效，则令牌越长，如果用户的机器受到威胁，攻击者将不得不冒充已验证用户的时间窗口就越大.

If you are protecting something extremely sensitive, you should keep the token lifetime to a very short window of time. If you are protecting something less sensitive, you could make the lifetime longer. The longer the token if valid, the larger the window of time a attacker will have to impersonate the authenticated user if the user's machine is compromised.

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