Using the HTTPClient and Sharepoint 2013 REST APIs

I am working in a .NET web application.I am trying to connect to Sharepoint Online Premise to get documents in the "Document Library" by using the HTTPClient and the Sharepoint 2013 REST API .

I tested the following rest service in the browser for this ,

   https://site_url/_vti_bin/ListData.svc/Documents

which gives the MetaData of all the documents present in the Document Library of the particular web site.

Now when i am trying to do the same programmatically by adding a reference to the service URL and by using the following code,

TestSiteDataContext ctx = new TestSiteDataContext(new Uri("https://site url/_vti_bin/ListData.svc"));
ctx.Credentials = new NetworkCredential("test@test.onmicrosoft.com", "test");
var data = ctx.Documents.ToList();

I am getting the following exception : "The request was aborted: Could not create SSL/TLS secure channel." The stack trace is as follows :

at System.Net.HttpWebRequest.GetResponse()
   at System.Data.Services.Client.QueryResult.Execute()
   at System.Data.Services.Client.DataServiceRequest.Execute[TElement](DataServiceContext context, QueryComponents queryComponents)
   at System.Data.Services.Client.DataServiceQuery`1.Execute()
   at System.Data.Services.Client.DataServiceQuery`1.GetEnumerator()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at SPO_AccessAWebService.Program.Main(String[] args) in Location\Program.cs:line 35
   at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
   at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
   at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()

I have gone through various articles/blogs to find a solution for this.Bust couldn't find any. I could see various samples tha shows authenticating by means of ,

ctx.Credentials = CredentialCache.DefaultNetworkCredentials;

This also is throwing the same error.

Is there is any other way to authenticate the SharePoint 2013 REST API?

Can someone provide me some insights to resolve this issue?

Based on the exception message you are reporting, it appears that the SSL cert is not valid for the site. I often see this message in development or test environments where self-signed cents are used. You should be able to tell if the cert is not valid if you have to click through a warning message when you visit the URL in a browser. To fix the issue, you can try connecting over http if transport security isn't a concern, obtain or install a valid cert, or import the current cert into Trusted Root Authorities store of the Current User or Local Machine.