要在ASP.NET Core中使用加密和SQL Server，可以使用以下步骤和代码示例：

1. 添加所需的依赖项： 在项目的.csproj文件中添加以下依赖项：

   运行dotnet restore命令以安装这些依赖项。

2. 在appsettings.json文件中配置数据库连接字符串：

   {
     "ConnectionStrings": {
       "DefaultConnection": "Server=;Database=;User Id=;Password=;"
     }
   }
   

3. 在Startup.cs文件中添加所需的服务：

   using Microsoft.AspNetCore.DataProtection;
   using Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption;
   using Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.ConfigurationModel;
   using Microsoft.AspNetCore.Builder;
   using Microsoft.AspNetCore.Hosting;
   using Microsoft.EntityFrameworkCore;
   using Microsoft.Extensions.Configuration;
   using Microsoft.Extensions.DependencyInjection;
   using Microsoft.Extensions.Hosting;
   
   namespace YourNamespace
   {
       public class Startup
       {
           private readonly IConfiguration _configuration;
           
           public Startup(IConfiguration configuration)
           {
               _configuration = configuration;
           }
           
           public void ConfigureServices(IServiceCollection services)
           {
               services.AddDbContext(options =>
                   options.UseSqlServer(_configuration.GetConnectionString("DefaultConnection")));
   
               services.AddDataProtection()
                   .PersistKeysToDbContext()
                   .UseCryptographicAlgorithms(new AuthenticatedEncryptorConfiguration()
                   {
                       EncryptionAlgorithm = EncryptionAlgorithm.AES_256_CBC,
                       ValidationAlgorithm = ValidationAlgorithm.HMACSHA256
                   });
               
               // 添加其他服务
           }
   
           public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
           {
               // 配置中间件
           }
       }
   }
   

4. 创建一个包含加密密钥的数据库上下文：

   using Microsoft.AspNetCore.DataProtection.EntityFrameworkCore;
   using Microsoft.EntityFrameworkCore;
   
   namespace YourNamespace
   {
       public class ApplicationDbContext : DbContext, IDataProtectionKeyContext
       {
           public ApplicationDbContext(DbContextOptions options) : base(options)
           {
           }
   
           public DbSet DataProtectionKeys { get; set; }
       }
   }
   

现在你可以在ASP.NET Core中使用加密和SQL Server了。