problems with System.Net.Security package

I am using package:

"System.Net.Security": "4.0.0-beta-22416"

PackageRestore works without any problems. But if my code execution gets to place where I am using System.Net.Security I get this error message:

Exception thrown: 'System.BadImageFormatException' in NetNextTest

Additional information: Could not load file or assembly 'System.Net.Security, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. Reference assemblies should not be loaded for execution. They can only be loaded in the Reflection-only loader context. (Exception from HRESULT: 0x80131058)

I am using version 1.0.0-rc1-update1 of vNext as well as most of the packages. Is there newer package (I need SslStream class) or mayby should I install something on my windows machine?

EDIT my project.json

{
  "userSecretsId": "(....)",
  "version": "1.0.0-*",  
  "compilationOptions": {
    "emitEntryPoint": true
  },

  "dependencies": {
    "EntityFramework.Commands": "7.0.0-rc1-final",
    "EntityFramework.MicrosoftSqlServer": "7.0.0-rc1-final",
    "Microsoft.AspNet.Authentication.Cookies": "1.0.0-rc1-final",
    "Microsoft.AspNet.Diagnostics.Entity": "7.0.0-rc1-final",
    "Microsoft.AspNet.Identity.EntityFramework": "3.0.0-rc1-final",
    "Microsoft.AspNet.IISPlatformHandler": "1.0.0-rc1-final",
    "Microsoft.AspNet.Hosting": "1.0.0-rc1-final",
    "Microsoft.AspNet.Server.WebListener": "1.0.0-rc1-final",
    "Microsoft.AspNet.Diagnostics": "1.0.0-rc1-final",
    "Microsoft.AspNet.Session": "1.0.0-rc1-final",
    "Microsoft.AspNet.Mvc": "6.0.0-rc1-final",
    "Microsoft.AspNet.Mvc.TagHelpers": "6.0.0-rc1-final",
    "Microsoft.AspNet.Server.Kestrel": "1.0.0-rc1-final",
    "Microsoft.AspNet.SignalR.Server": "3.0.0-rc1-final",
    "Microsoft.AspNet.StaticFiles": "1.0.0-rc1-final",
    "Microsoft.AspNet.Tooling.Razor": "1.0.0-rc1-final",
    "Microsoft.Extensions.CodeGenerators.Mvc": "1.0.0-rc1-final",
    "Microsoft.Extensions.Configuration.FileProviderExtensions": "1.0.0-rc1-final",
    "Microsoft.Extensions.Configuration.Json": "1.0.0-rc1-final",
    "Microsoft.Extensions.Configuration.UserSecrets": "1.0.0-rc1-final",
    "Microsoft.Extensions.Logging": "1.0.0-rc1-final",
    "Microsoft.Extensions.Logging.Console": "1.0.0-rc1-final",
    "Microsoft.Extensions.Logging.Debug": "1.0.0-rc1-final",
    "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0-rc1-final",
    "System.Threading.Timer": "4.0.1-beta-23516",
    "System.Net.Security": "4.0.0-beta-23516",
    "System.Security.Cryptography.Encoding": "4.0.0-beta-23409" 
  },
  "commands": {
    "gen": "Microsoft.Framework.CodeGeneration",
    "kestrel": "Microsoft.AspNet.Hosting --server Kestrel --server.urls http://localhost:5004",
    "run": "run server.urls=http://localhost:5003",
    "web": "Microsoft.AspNet.Hosting --server Microsoft.AspNet.Server.WebListener --server.urls http://localhost:5001"
  },

  "frameworks": {
    "dnxcore50": { }
  },

  "exclude": [
    "wwwroot"
  ],
  "publishExclude": [
    "**.user",
    "**.vspscc"
  ],
  "scripts": {
    "prepublish": [ "npm install", "bower install", "gulp clean", "gulp min" ]
  }
}