如何加密JWT安全令牌？

Question

我需要使用签名和加密来保护我的网络令牌。我编写了下面的代码：

var tokenHandler = new JwtSecurityTokenHandler();
var tokenDescriptor = new SecurityTokenDescriptor
{
      Subject = new ClaimsIdentity(new[]
         {
             new Claim(ClaimTypes.Name, owner.Name),
             new Claim(ClaimTypes.Role, owner.RoleClaimType),
             new Claim("custom claim type", "custom content")
         }),
      TokenIssuerName = "self",
      AppliesToAddress = "http://www.example.com",
      Lifetime = new Lifetime(now, now.AddSeconds(60 * 3)),
      EncryptingCredentials = new X509EncryptingCredentials(new X509Certificate2(cert)),
      SigningCredentials = new X509SigningCredentials(cert1)
};
var token = (JwtSecurityToken)tokenHandler.CreateToken(tokenDescriptor);            
var tokenString = tokenHandler.WriteToken(token);

所以，我正在使用一些由 makecert.exe 生成的证书。然后我使用另一个 JwtSecurityTokenHandler 读取令牌字符串：

var tokenHandlerDecr = new JwtSecurityTokenHandler();
var tok = tokenHandlerDecr.ReadToken(tokenString);

令牌内容未加密（我可以在调试器下的tok变量中看到JSON）。我做错了什么？如何加密令牌数据？

- Qué Padre

Answer 1

我知道这是一个老帖子，但如果有人仍在寻找答案，我会添加我的答案。

这个问题在Microsoft.IdentityModel.Tokens版本5.1.3中得到解决。 CreateJwtSecurityToken函数中有一个可重载的方法，它接受加密凭据以加密令牌。

如果接收方不验证签名并尝试直接读取JWT，则声明为空。以下是代码片段：

using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;

const string sec = "ProEMLh5e_qnzdNUQrqdHPgp";
const string sec1 = "ProEMLh5e_qnzdNU";
var securityKey = new SymmetricSecurityKey(Encoding.Default.GetBytes(sec));
var securityKey1 = new SymmetricSecurityKey(Encoding.Default.GetBytes(sec1)); 

var signingCredentials = new SigningCredentials(
    securityKey,
    SecurityAlgorithms.HmacSha512);

List<Claim> claims = new List<Claim>()
{
    new Claim("sub", "test"),
};

var ep = new EncryptingCredentials(
    securityKey1,
    SecurityAlgorithms.Aes128KW,
    SecurityAlgorithms.Aes128CbcHmacSha256);

var handler = new JwtSecurityTokenHandler();

var jwtSecurityToken = handler.CreateJwtSecurityToken(
    "issuer",
    "Audience",
    new ClaimsIdentity(claims),
    DateTime.Now,
    DateTime.Now.AddHours(1),
    DateTime.Now,
    signingCredentials,
    ep);


string tokenString = handler.WriteToken(jwtSecurityToken);

// Id someone tries to view the JWT without validating/decrypting the token,
// then no claims are retrieved and the token is safe guarded.
var jwt = new JwtSecurityToken(tokenString);

以下是验证/解密令牌的代码：

using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;

const string sec = "ProEMLh5e_qnzdNUQrqdHPgp";
const string sec1 = "ProEMLh5e_qnzdNU";
var securityKey = new SymmetricSecurityKey(Encoding.Default.GetBytes(sec));
var securityKey1 = new SymmetricSecurityKey(Encoding.Default.GetBytes(sec1));

// This is the input JWT which we want to validate.
string tokenString = string.Empty;

// If we retrieve the token without decrypting the claims, we won't get any claims
// DO not use this jwt variable
var jwt = new JwtSecurityToken(tokenString);

// Verification
var tokenValidationParameters = new TokenValidationParameters()
{
    ValidAudiences = new string[]
    {
        "536481524875-glk7nibpj1q9c4184d4n3gittrt8q3mn.apps.googleusercontent.com"
    },
    ValidIssuers = new string[]
    {
        "https://accounts.google.com"
    },
    IssuerSigningKey = securityKey,
    // This is the decryption key
    TokenDecryptionKey = securityKey1
};

SecurityToken validatedToken;
var handler = new JwtSecurityTokenHandler();

handler.ValidateToken(tokenString, tokenValidationParameters, out validatedToken);

- Amey

---

由于在验证令牌时没有传递密钥的选项，我应该如何解密令牌？ - Sang Suantak

@SangSuantak TokenValidationParameters有TokenDecryptionKey属性。验证器内部使用此属性来解密令牌。我已更新我的答案，包括解密部分。 - Amey

@Amey，我们可以使用公钥私钥对来加密和解密JWT令牌吗？如果可以，怎么做？ - Rajat Agrawal

@JacobStamm 那个页面怎么说 IdentityModel 已经被弃用了？只有 WCF 被弃用了，WIF 没有。 - Franklin Yu

@Amey 这个过程输出的令牌带有头部声明中的 "alg": "A128KW", "enc": "A128CBC-HS256"。"enc"参数看起来符合预期，但是"alg"不应该保持为"HS256"吗？ - Beltway

Answer 2

请尝试以下示例

更新于2019年7月: .NET Core, Asp.net Core

1. 创建JWT

private string CreateJwt(string sub, string jti, string issuer, string audience)
{
    var claims = new[]
    {
        new Claim(JwtRegisteredClaimNames.Sub, sub),
        new Claim(JwtRegisteredClaimNames.Jti, jti),
    };

    var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes("SecretKeySecretKeySecretKeySecretKeySecretKeySecretKeySecretKeyS"));
    var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
    var encryptingCredentials = new EncryptingCredentials(key, JwtConstants.DirectKeyUseAlg, SecurityAlgorithms.Aes256CbcHmacSha512);

    var jwtSecurityToken = new JwtSecurityTokenHandler().CreateJwtSecurityToken(
        issuer,
        audience,
        new ClaimsIdentity(claims),
        null,
        expires: DateTime.UtcNow.AddMinutes(5),
        null,
        signingCredentials: creds,
        encryptingCredentials: encryptingCredentials
        );
    var encryptedJWT = new JwtSecurityTokenHandler().WriteToken(jwtSecurityToken);

    return encryptedJWT;
}

2. 在Startup.cs中添加到ConfigureServices(IServiceCollection services)方法中。

    services.AddAuthentication(options =>
{
    options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
})
.AddJwtBearer(options =>
{
    options.TokenValidationParameters = new TokenValidationParameters
    {
        ValidateIssuer = true,
        ValidateAudience = true,
        ValidateLifetime = true,
        ValidateIssuerSigningKey = true,

        ValidIssuer = (string)Configuration.GetSection("JwtToken").GetValue(typeof(string), "Issuer"),
        ValidAudience = (string)Configuration.GetSection("JwtToken").GetValue(typeof(string), "Audience"),
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes("SecretKeySecretKeySecretKeySecretKeySecretKeySecretKeySecretKeyS")),
        TokenDecryptionKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes("SecretKeySecretKeySecretKeySecretKeySecretKeySecretKeySecretKeyS")),
        ClockSkew = TimeSpan.FromMinutes(0),
    };
});

- Hung Quach

---

你能分析并帮我解决代码中的问题吗？从请求中接收Token，然后解码并与存储的数据Token进行比较。这段代码可以正常运行，但我不明白它是如何工作的。谢谢！ - Trang Đỗ

Answer 3

我的理解是，微软的JWT实现目前不支持加密（只支持签名）。

- Brock Allen

---

如果可以的话，我真的很感激您能够提供一些关于这个主题的链接。 - Qué Padre

我已经探索了这个扩展，看起来你是对的 - 目前还不支持加密。谢谢！ - Qué Padre

这还是现状吗？ - Dan Turner

据我所知，是的。 - Brock Allen

有没有其他方法可以实现这个功能？有没有可以使用的库或覆盖JwtSecurityTokenHandler的方法？ - SachiraChin

此问题已在 Microsoft.IdentityModel.Tokens 版本 5.1.3 中得到解决。有关详细信息，请参阅我的答案。 - Amey

Answer 4

Hung Quach的回答在我的.NET 5上的Blazor工作得非常好。虽然我为了自己的风格稍微改变了一下它。

   var claims = new List<Claim>()
            {
                new Claim(ClaimTypes.Name,userRequestDTO.Email)
            };
            var secret = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_APISettings.SecretKey));
            var signingCredentials = new SigningCredentials(secret, SecurityAlgorithms.HmacSha256);
            var encryptionCredentials = new EncryptingCredentials(secret, JwtConstants.DirectKeyUseAlg, SecurityAlgorithms.Aes256CbcHmacSha512);
            var tokenOptions = new JwtSecurityTokenHandler().CreateJwtSecurityToken(new SecurityTokenDescriptor()
            {
                Audience= _APISettings.ValidAudience,
                Issuer= _APISettings.ValidIssuer,
                Subject= new ClaimsIdentity(claims),
                Expires= DateTime.Now.AddMinutes(10),
                EncryptingCredentials= encryptionCredentials,
                SigningCredentials = signingCredentials
            });

            return new JwtSecurityTokenHandler().WriteToken(tokenOptions);

然后我按以下方式读取令牌：

 JwtSecurityTokenHandler tokenHandler = new JwtSecurityTokenHandler();
                var secret = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_APISettings.SecretKey));
                var signingCredentials = new SigningCredentials(secret, SecurityAlgorithms.HmacSha256);

                tokenHandler.ValidateToken(tokenOTP,new TokenValidationParameters
                {
                    ValidIssuer = _APISettings.ValidIssuer,
                    ValidAudience = _APISettings.ValidAudience,
                    ValidateIssuerSigningKey=true,
                    ValidateLifetime = true,
                    RequireExpirationTime = true,
                    ValidateIssuer = true,
                    ValidateAudience = true,
                    IssuerSigningKey= secret,
                    TokenDecryptionKey=secret,
                    ClockSkew = TimeSpan.Zero
                },out SecurityToken validatedToken);
                var jwtToken = (JwtSecurityToken)validatedToken;

- MrSpyretos