从' WP8 '应用程序使用' HttpClient '对REST服务进行身份验证的问题

我试图连接我的应用程序与一些需要身份验证的Rest服务，我有一些问题。我使用HttpClient类，它可以很好地与不需要此身份验证的服务(如登录或注册)一起工作。我认为问题是我需要在AuthenticationHeaderValue对象中指定一个模式，这个模式进入标题。报头的结果类似于"Authorization: Authorization a81b4974-f328-44e0-901a-95e29fb672aa:sKJQgOqJswCLHlibsMGRYZb/dlkyPzVnvs9uqqx5ToM="，而服务器正在查找的是类似于"Authorization: a81b4974-f328-44e0-901a-95e29fb672aa:sKJQgOqJswCLHlibsMGRYZb/dlkyPzVnvs9uqqx5ToM="的内容。下面是我使用的代码:

public async void addProject(string name) 
{
    string service = "/service/project/add";
    string serviceURL = "/pwpcloud"+service;
    StringBuilder parametersBuilder = new StringBuilder();
    parametersBuilder.Append("{'"name'":'"" + name + "'",");
    parametersBuilder.Append("'"description'":'"" + "projectDescription" + "'",");
    parametersBuilder.Append("'"sparsePath'":'"" + "fasdd" + "'",");
    parametersBuilder.Append("'"densePath'":'"" + "asdf" + "'",");
    parametersBuilder.Append("'"matchFormat'":'"" + "asdf" + "'",");
    parametersBuilder.Append("'"metadata'":'"" + "aaaaa" + "'",");
    parametersBuilder.Append("'"user'":'"" + mLoginData.getUserID() + "'"}");
    string parameters = parametersBuilder.ToString();
    HttpClient restClient = new HttpClient();
    restClient.BaseAddress = new Uri(mBaseURL);
    restClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    //falta la autenticacion
    setAuthorization(restClient, service, WEBSERVICE_REQUEST_TYPE_POST);
    HttpRequestMessage req = new HttpRequestMessage(HttpMethod.Post, serviceURL);
    req.Content = new StringContent(parameters, Encoding.UTF8, "application/json");
    HttpResponseMessage response = null;
    string responseBodyAsText = "";
    try
    {
        response = await restClient.SendAsync(req);
        response.EnsureSuccessStatusCode();
        responseBodyAsText = await response.Content.ReadAsStringAsync();
    }
    catch (HttpRequestException e)
    {
        string ex = e.Message;
    }
}
public void setAuthorization(HttpClient request, string service, int reqType, string token, string userID)
{
    //Date OK
    string date = DateTime.UtcNow.ToString("yyyy-MM-ddTHH:mm:ssZ");
    //nonce OK
    Random random = new Random();
    String nonce = "";
    for (int i = 0; i < 5; i++)
    {
        string randomValue = (1111 + random.Next() % (9999 - 1111)).ToString();
        nonce = nonce + randomValue;
    }
    //type OK
    string type = "";
    if (reqType == WEBSERVICE_REQUEST_TYPE_GET)
    {
        type = "GET";
    }
    else
    {
        type = "POST";
    }
    //Authorization:
    string stringToHash = token + ":" + service + "," + type + "," + date + "," + nonce;
    string authorizationCrypted = encryptStringSHA256(stringToHash);
    //string authorization = userID + ":" + authorizationCrypted;
    request.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Authorization", string.Format("{0}:{1}", userID, authorizationCrypted));
    request.DefaultRequestHeaders.Add("x-rest-date", date);
    request.DefaultRequestHeaders.Add("nonce", nonce);
}
public static string encryptStringSHA256(string stringToEncrypt)
{
    var hash = new SHA256Managed();
    byte[] stringHash = StringToAscii(stringToEncrypt);
    byte[] encryptedString = hash.ComputeHash(stringHash);
    return Convert.ToBase64String(encryptedString);
}
//Metodo para convertir string a bytes ascii NO IMPLEMENTADO POR DEFECTO EN EL API DE WINDOWS PHONE
public static byte[] StringToAscii(string s)
{
    byte[] retval = new byte[s.Length];
    for (int ix = 0; ix < s.Length; ++ix)
    {
        char ch = s[ix];
        if (ch <= 0x7f) retval[ix] = (byte)ch;
        else retval[ix] = (byte)'?';
    }
    return retval;
}

谢谢你的帮助。

public void setAuthorization(HttpClient request, string service, int reqType, string token, string userID)
{
    //Date OK
    string date = DateTime.UtcNow.ToString("yyyy-MM-ddTHH:mm:ssZ");
    //nonce OK
    Random random = new Random();
    String nonce = "";
    for (int i = 0; i < 5; i++)
    {
        string randomValue = (1111 + random.Next() % (9999 - 1111)).ToString();
        nonce = nonce + randomValue;
    }
    //type OK
    string type = "";
    if (reqType == WEBSERVICE_REQUEST_TYPE_GET)
    {
        type = "GET";
    }
    else
    {
        type = "POST";
    }
    //Authorization:
    string stringToHash = token + ":" + service + "," + type + "," + date + "," + nonce;
    string authorizationCrypted = encryptStringSHA256(stringToHash);
    string authorization = userID + ":" + authorizationCrypted;
    request.DefaultRequestHeaders.TryAddWithoutValidation("x-rest-date", date);
    request.DefaultRequestHeaders.TryAddWithoutValidation("Authorization", authorization);
    request.DefaultRequestHeaders.TryAddWithoutValidation("nonce", nonce);
}