Skip to main content

Windows Live - Web Authentication

Windows LIVE series:
Live ID se poate folosii pentru doua lucruri:
  • autentificarea userilor in aplicatia noastra folosind contul de Live ID
  • accesul aplicatiei noastre la servicii pe care un user de LIVE ID are access( photo sharing, agenda, calendar, etc)
Astazi o sa discutam despre cum poate un utilizator sa se autentifice in aplicatia noastra folosind contul de de Live ID.
Mai jos o sa prezint vechiul mod de autentificare, care a devenit absolute, odata cu lansarea "Live Connect", despre care o sa povestim cat de curand. Prefer sa prezint si acest mecanism in cazul in care lucrati cu aplicatii deja facute care folosesc vechiul mecanism de autentificare.
Acest mecanism de autentificare a fost denumit de cei de la Microsoft "Windows Live ID Web Authetification", dar nu are nimic mai special. In momentul in care userul doreste sa se autentifice, acesta este redirectat spre pagina Windows Live ID, unde isi va introduce datele. Dupa acest pas, userul este redirectat inapoi spre aplicatia noastra cu o cheie unica( token) - denumita Cliend ID, pe baza careia putem sa identificam userul. Pe langa aceste informatii, avem access la cateva date de baza a userului precum nume, tara, etc.
Cliend ID este o cheie unica formata din 16 caractere, pe care o sa trasmiteti la servere Windows Live de fiecare data cand un user se autentifica. Toate datele care se trasmit o sa fie encriptate si semntate pe baza unuei chei secrete pe care o primiti in momentul in care va inregistrati aplicatia.
Primul pas pe care trebuie sa il facem este sa ne inregistram aplicatia. Fiecare aplicatie se identifica unic pe baza unei chei. Acest lucru se poate face la urmatorul link: http://go.microsoft.com/fwlink/?LinkID=144070
Odata ce avem aplicatia inregistrata, trebuie sa adaugam in aplicatia noastra un link de autentificare prin Live ID. Acest link o sa contina ca si parametrii:
  • appid - cliend ID( cheia unica a aplicatiei noastre)
  • context -( optional) pagina spre care userul sa fie redirectionat dupa ce autentificarea se finalizeaza( ex. welcome.html)
  • style -( optional) o colectie de atribute folosite prin care se poate personaliza bunoul de sign in
Dupa ce userul isi introduce credentiale o sa fie redirectionat spre pagina noastra. Pe flowul normal, in cookies o sa gasim un token encriptat cu cheia "webauthtoken". Acesta o sa contina urmatoarele date despre user:
  • User.Id – id-ul unic a fiecarui user
  • User.Timestamp – data ultimei autentificari
  • User.Context – contextul care a fost specificat in momentul autentificarii
  • User.Token – token-ul unic a userului curent( dupa o anumita perioada de timp acesta o sa expire)
Trebuie precizat ca datele sunt encriptate este AES128, iar cel de semnare este HMAC-SHA256. Mai jos gasiti un exemplu de cum trebuie facuta decriptatea si extragerea datelor.
public string DecryptResponse(){     const int ivLength = 16;     token = HttpUtility.UrlDecode(token);     byte[] ivAndEncryptedValue = Convert.FromBase64String(token);     var decryptAlg = new RijndaelManaged();     decryptAlg.KeySize = 128;     decryptAlg.Key = cryptKey;     decryptAlg.Padding = PaddingMode.PKCS7;     var memStream = new MemoryStream(ivAndEncryptedValue);     byte[] iv = new byte[ivLength];     memStream.Read(iv, 0, ivLength);     decryptAlg.IV = iv;     cStream = new CryptoStream(memStream, decryptAlg.CreateDecryptor(),                          CryptoStreamMode.Read);     sReader = new StreamReader(cStream, Encoding.ASCII);     return sReader.ReadToEnd();}

In urmatorul post o sa discutam despre Live Connect.

Comments

Popular posts from this blog

Windows Docker Containers can make WIN32 API calls, use COM and ASP.NET WebForms

After the last post , I received two interesting questions related to Docker and Windows. People were interested if we do Win32 API calls from a Docker container and if there is support for COM. WIN32 Support To test calls to WIN32 API, let’s try to populate SYSTEM_INFO class. [StructLayout(LayoutKind.Sequential)] public struct SYSTEM_INFO { public uint dwOemId; public uint dwPageSize; public uint lpMinimumApplicationAddress; public uint lpMaximumApplicationAddress; public uint dwActiveProcessorMask; public uint dwNumberOfProcessors; public uint dwProcessorType; public uint dwAllocationGranularity; public uint dwProcessorLevel; public uint dwProcessorRevision; } ... [DllImport("kernel32")] static extern void GetSystemInfo(ref SYSTEM_INFO pSI); ... SYSTEM_INFO pSI = new SYSTEM_INFO(

Azure AD and AWS Cognito side-by-side

In the last few weeks, I was involved in multiple opportunities on Microsoft Azure and Amazon, where we had to analyse AWS Cognito, Azure AD and other solutions that are available on the market. I decided to consolidate in one post all features and differences that I identified for both of them that we should need to take into account. Take into account that Azure AD is an identity and access management services well integrated with Microsoft stack. In comparison, AWS Cognito is just a user sign-up, sign-in and access control and nothing more. The focus is not on the main features, is more on small things that can make a difference when you want to decide where we want to store and manage our users.  This information might be useful in the future when we need to decide where we want to keep and manage our users.  Feature Azure AD (B2C, B2C) AWS Cognito Access token lifetime Default 1h – the value is configurable 1h – cannot be modified

What to do when you hit the throughput limits of Azure Storage (Blobs)

In this post we will talk about how we can detect when we hit a throughput limit of Azure Storage and what we can do in that moment. Context If we take a look on Scalability Targets of Azure Storage ( https://azure.microsoft.com/en-us/documentation/articles/storage-scalability-targets/ ) we will observe that the limits are prety high. But, based on our business logic we can end up at this limits. If you create a system that is hitted by a high number of device, you can hit easily the total number of requests rate that can be done on a Storage Account. This limits on Azure is 20.000 IOPS (entities or messages per second) where (and this is very important) the size of the request is 1KB. Normally, if you make a load tests where 20.000 clients will hit different blobs storages from the same Azure Storage Account, this limits can be reached. How we can detect this problem? From client, we can detect that this limits was reached based on the HTTP error code that is returned by HTTP