.NET6之MiniAPI(十六)：数据保护

Posted 2022-02-24 dotNET跨平台

对于web，安全是一个永久的话题，所以ASP.NET Core数据保护提供了一个简单，易用的加密API，可以用来保护数据，密钥管理和轮换。

ASP.NET Core的数据保护是根据本机的一个key来生成加密码，然后再用这个key来解密，如果key不一样，解密失败。默认情况下这个key的有效期是90天，当然这个值是可以被改变的。

默认数据保护key存放的位置，C:\\Users\\用户\\AppData\\Local\\ASP.NET\\DataProtection-Keys，如：key-a2b3132b-444b-4cfa-8530-922b7e991cd9.xml，是一个xml文件，里面记录了这个key的一些信息，创建时间，激活时间，过期时间，和加解密数据所用的命名空间，加密方式等信息，如下：

<?xml version="1.0" encoding="utf-8"?>
<key id="a2b3132b-444b-4cfa-8530-922b7e991cd9" version="1">
  <creationDate>2022-02-10T13:41:14.7492868Z</creationDate>
  <activationDate>2022-02-10T13:41:14.7421157Z</activationDate>
  <expirationDate>2022-05-11T13:41:14.7421157Z</expirationDate>
  <descriptor deserializerType="Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.ConfigurationModel.AuthenticatedEncryptorDescriptorDeserializer, Microsoft.AspNetCore.DataProtection, Version=6.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60">
    <descriptor>
      <encryption algorithm="AES_256_CBC" />
      <validation algorithm="HMACSHA256" />
      <encryptedSecret decryptorType="Microsoft.AspNetCore.DataProtection.XmlEncryption.DpapiXmlDecryptor, Microsoft.AspNetCore.DataProtection, Version=6.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60" xmlns="http://schemas.asp.net/2015/03/dataProtection">
        <encryptedKey xmlns="">
          <!-- This key is encrypted with Windows DPAPI. -->
          <value>AQAAANCMnd8BFdERjHoAwE/Cl+sBAAAAAZeuIp6hZUGsfTgUuNoSSAAAAAACAAAAAAAQZgAAAAEAACAAAACpVhXOBzCWDrZmD13HwR6U3qHk7O2Pki1vPEBrtOJlrQAAAAAOgAAAAAIAACAAAAAPc2zwN10L4IVtN7tFsdQV0Cx7giHlNrWI6heArHHFt1ABAAACCCC8BhZwQ32ZZ67nBEi/tZS+HagViuS/xYtlUJOfzkJOmWg28KkBR2vM6Jo1Y1OY/AbIx6EhbGvZUkdL9aeGBy6A0GBS/3VC4/X8KV3sihRPhb1n924slVds0Y9p7J3p6sCLbhvh0ohhBe1pAENr1XkUnd2Ve4JQ0gVVgQ7vFJOonGGXGQ52dzmITzkJLYIqwNtksA31OmJUlJG7KJnrDEofKjQynvj9gXnOVnMpfHNk6v8v96WDlK7n9Ax3o/W238E7FtOVBKTNoIFWwyc40MR25IrkQdtMZ7HrODY1VRL9nuuexbVXq+5mt5QOyVgvZ1RK0sCwaBB3FSHwKmjskk+WpHXZpi3hjLx82F1gCpatSma01zDEDte0LZHRG9pVYgUXRwUaXX3G0uPuI2mXNpN57qIGZhCJC37cACIzJQ5NxuS+n9Rs6SjVykn78LBAAAAAkxOreUFzysrk5EeldARfOulsq/9OT2w/AFU9sRvPWgZPOieKcdAfIuNF09FgcyquX6IcNuydPn46Uy+saHia0w==</value>
        </encryptedKey>
      </encryptedSecret>
    </descriptor>
  </descriptor>
</key>

使用数据保护的代码也很简单，注入DataProtection服务就可以，只需要使用服务时，通过IDataProtectionProvider创建一个数据保护对象，在创建时可以添加目标字符串参数，来防隔离不同的目标字符串加密的数据，所以key和这个目标字符串都能起到隔离作用。

using Microsoft.AspNetCore.DataProtection;


var builder = WebApplication.CreateBuilder(args);
//通过SetDefaultKeyLifetime更改默认值90天
builder.Services.AddDataProtection().SetDefaultKeyLifetime(TimeSpan.FromDays(10));
var app = builder.Build();


app.MapGet("/encrypt/str", (IDataProtectionProvider provider, ILogger<Program> logger, string str) =>

    var protector = provider.CreateProtector("a.b.c");
    var sec = protector.Protect(str);
    logger.LogInformation(sec);
    return "加密：" + sec;
);
app.MapGet("/decrypt/sec", (IDataProtectionProvider provider, ILogger<Program> logger, string sec) =>

    var protector = provider.CreateProtector("a.b.c");
    var str = protector.Unprotect(sec);
    logger.LogInformation(str);
    return "解密：" + str;
);


app.Run();

上面代码只是实现了单机部署，如果集群部署，比如k8s中的不同pod，生成的key分别保存在自己的pod里，那么外部访问又是随机分配的，这时就会频繁出现解密失败的情况，这就要集中管理key了，用redis或数据库都可以，这里用到的是SqlServer，首先创建存key的表，如下：

CREATE TABLE [dbo].[DataProtectionKeys1](
  [ID] [int] IDENTITY(1,1) NOT NULL PRIMARY KEY ,
  [FriendlyName] [varchar](64) NULL,
  [Xml] [text] NULL
 )

当有key保存进来时的结果如下：

其中字段key存的值如下，与本地文件存储的是一样的。

<key id="a32def14-9156-4c5e-946c-d3aa5b1a1743" version="1"> 
  <creationDate>2022-02-10T14:20:37.5680295Z</creationDate>  
  <activationDate>2022-02-10T14:20:36.5853181Z</activationDate>  
  <expirationDate>2022-05-11T14:20:36.5853181Z</expirationDate>  
  <descriptor deserializerType="Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.ConfigurationModel.AuthenticatedEncryptorDescriptorDeserializer, Microsoft.AspNetCore.DataProtection, Version=6.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60"> 
    <descriptor> 
      <encryption algorithm="AES_256_CBC"/>  
      <validation algorithm="HMACSHA256"/>  
      <masterKey xmlns:p4="http://schemas.asp.net/2015/03/dataProtection" p4:requiresEncryption="true">  
        <!-- Warning: the key below is in an unencrypted form. -->  
        <value>gO70+leJQM8NJopS5VmMy+qkz0j+I9diBoCnxkqGxpqdXmyTULgAhMyu+3S4SJ0vjsx8Hxc+d/ipUgDBnkuQNw==</value> 
      </masterKey> 
    </descriptor> 
  </descriptor> 
</key>

这时，代码需要支持EF，所以引入如下NuGet包

Microsoft.AspNetCore.DataProtection Microsoft.AspNetCore.DataProtection.EntityFrameworkCore Microsoft.EntityFrameworkCore 

Microsoft.EntityFrameworkCore.SqlServer

代码要换成EF方式持久化key，要注入EF的Context，然后注入数据保护对象时指明持久化的方式：

using Microsoft.AspNetCore.DataProtection;
using Microsoft.AspNetCore.DataProtection.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;


var builder = WebApplication.CreateBuilder(args);


builder.Services.AddDbContext<DataProtContext>(options =>
      options.UseSqlServer(builder.Configuration.GetConnectionString("DataProtDB")));
builder.Services.AddDataProtection().PersistKeysToDbContext<DataProtContext>();
var app = builder.Build();


app.MapGet("/encrypt/str", (IDataProtectionProvider provider, ILogger<Program> logger, string str) =>

    var protector = provider.CreateProtector("a.b.c");
    var sec = protector.Protect(str);
    logger.LogInformation(sec);
    return "加密：" + sec;
);
app.MapGet("/decrypt/sec", (IDataProtectionProvider provider, ILogger<Program> logger, string sec) =>

    var protector = provider.CreateProtector("a.b.c");
    var str = protector.Unprotect(sec);
    logger.LogInformation(str);
    return "解密：" + str;
);


app.Run();


class DataProtContext : DbContext, IDataProtectionKeyContext

    public DbSet<DataProtectionKey> DataProtectionKeys  get; set; 


    public DataProtContext(DbContextOptions<DataProtContext> options)
          : base(options)
    

加密结果：

解密结果：

如果生成的加密串需要时效性，需要把生成的Protector转成TimeLimitedDataProtector来加解密，如下：

……
app.MapGet("/encrypt/str", (IDataProtectionProvider provider, ILogger<Program> logger, string str) =>

    var protector = provider.CreateProtector("a.b.c");
    var sec = protector.ToTimeLimitedDataProtector().Protect(str, TimeSpan.FromSeconds(30));
    logger.LogInformation(sec);
    return "加密：" + sec;
);
app.MapGet("/decrypt/sec", (IDataProtectionProvider provider, ILogger<Program> logger, string sec) =>

    var protector = provider.CreateProtector("a.b.c");
    var str = protector.ToTimeLimitedDataProtector().Unprotect(sec);
    logger.LogInformation(str);
    return "解密：" + str;
);


……

如果加密串过期提交，报错如下：