diff --git a/src/WindreamHub.Legacy.Client/Models/Authentication/Base64Credential.cs b/src/WindreamHub.Legacy.Client/Models/Authentication/Base64Credential.cs
new file mode 100644
index 0000000..b4828df
--- /dev/null
+++ b/src/WindreamHub.Legacy.Client/Models/Authentication/Base64Credential.cs
@@ -0,0 +1,9 @@
+namespace WindreamHub.Legacy.Client.Models.Authentication
+{
+    public class Base64Credential : ICredential
+    {
+        public Base64Credential(string authorizationHeader) => AuthorizationHeader = authorizationHeader;
+
+        public string AuthorizationHeader { get; }
+    }
+}
\ No newline at end of file
diff --git a/src/WindreamHub.Legacy.Client/Models/Authentication/ErrorDetails.cs b/src/WindreamHub.Legacy.Client/Models/Authentication/ErrorDetails.cs
new file mode 100644
index 0000000..546c959
--- /dev/null
+++ b/src/WindreamHub.Legacy.Client/Models/Authentication/ErrorDetails.cs
@@ -0,0 +1,9 @@
+namespace WindreamHub.Legacy.Client.Models.Authentication
+{
+    public class ErrorDetails
+    {
+        public ErrorItem Item { get; set; }
+        public string Message { get; set; }
+        public int ErrorCode { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/src/WindreamHub.Legacy.Client/Models/Authentication/ErrorItem.cs b/src/WindreamHub.Legacy.Client/Models/Authentication/ErrorItem.cs
new file mode 100644
index 0000000..12ad748
--- /dev/null
+++ b/src/WindreamHub.Legacy.Client/Models/Authentication/ErrorItem.cs
@@ -0,0 +1,10 @@
+namespace WindreamHub.Legacy.Client.Models.Authentication
+{
+    public class ErrorItem
+    {
+        public int Entity { get; set; }
+        public int Id { get; set; }
+        public string Location { get; set; }
+        public string Name { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/src/WindreamHub.Legacy.Client/Models/Authentication/ICredential.cs b/src/WindreamHub.Legacy.Client/Models/Authentication/ICredential.cs
new file mode 100644
index 0000000..d4285ab
--- /dev/null
+++ b/src/WindreamHub.Legacy.Client/Models/Authentication/ICredential.cs
@@ -0,0 +1,7 @@
+namespace WindreamHub.Legacy.Client.Models.Authentication
+{
+    public interface ICredential
+    {
+        string AuthorizationHeader { get; }
+    }
+}
\ No newline at end of file
diff --git a/src/WindreamHub.Legacy.Client/Models/UserCredential.cs b/src/WindreamHub.Legacy.Client/Models/Authentication/UserCredential.cs
similarity index 58%
rename from src/WindreamHub.Legacy.Client/Models/UserCredential.cs
rename to src/WindreamHub.Legacy.Client/Models/Authentication/UserCredential.cs
index 7575c8d..3d8844b 100644
--- a/src/WindreamHub.Legacy.Client/Models/UserCredential.cs
+++ b/src/WindreamHub.Legacy.Client/Models/Authentication/UserCredential.cs
@@ -1,15 +1,16 @@
 using System;
 using System.Text;
+using WindreamHub.Legacy.Client.Models.Authentication;
 
 namespace WindreamHub.Legacy.Client.Models
 {
-    public class UserCredential
+    public class UserCredential : ICredential
     {
         public readonly string Domain;
 
         public readonly string Name;
 
-        public readonly string AuthorizationHeader;
+        public string AuthorizationHeader { get; }
 
         public UserCredential(string domain, string name, string password)
         {
@@ -20,9 +21,9 @@ namespace WindreamHub.Legacy.Client.Models
 
         private static string ConvertToBase64(string domain, string username, string password)
         {
-            string credentials = $"{domain}\\{username}:{password}";
-            byte[] bytes = Encoding.UTF8.GetBytes(credentials);
-            return Convert.ToBase64String(bytes);
+            var credentials = $"{domain}\\{username}:{password}";
+            var base64Credentials = Convert.ToBase64String(System.Text.Encoding.ASCII.GetBytes(credentials));
+            return base64Credentials;
         }
     }
 }
\ No newline at end of file
diff --git a/src/WindreamHub.Legacy.Client/Models/Authentication/ValidationResponse.cs b/src/WindreamHub.Legacy.Client/Models/Authentication/ValidationResponse.cs
new file mode 100644
index 0000000..1603a1e
--- /dev/null
+++ b/src/WindreamHub.Legacy.Client/Models/Authentication/ValidationResponse.cs
@@ -0,0 +1,15 @@
+using System.Collections.Generic;
+
+namespace WindreamHub.Legacy.Client.Models.Authentication
+{
+    public class ValidationResponse
+    {
+        public int UserID { get; set; }
+        public string UserName { get; set; }
+        public string FullUserName { get; set; }
+        public bool IsValidUser { get; set; }
+        public ErrorDetails Error { get; set; }
+        public List<ErrorDetails> Errors { get; set; }
+        public bool HasErrors { get; set; }
+    }
+}
diff --git a/src/WindreamHub.Legacy.Client/Models/ModelExtensions.cs b/src/WindreamHub.Legacy.Client/Models/ModelExtensions.cs
index eb17e45..7164799 100644
--- a/src/WindreamHub.Legacy.Client/Models/ModelExtensions.cs
+++ b/src/WindreamHub.Legacy.Client/Models/ModelExtensions.cs
@@ -3,6 +3,7 @@ using System;
 using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
+using Newtonsoft.Json;
 
 namespace WindreamHub.Legacy.Client.Models
 {
@@ -89,5 +90,7 @@ namespace WindreamHub.Legacy.Client.Models
                     error?.Invoke(res.Error);
             });
         }
+
+        public static string Stringify(this object model) => JsonConvert.SerializeObject(model);
     }
 }
\ No newline at end of file
diff --git a/src/WindreamHub.Legacy.Client/Routes/AuthenticationRouteService.cs b/src/WindreamHub.Legacy.Client/Routes/AuthenticationRouteService.cs
index 6eec24f..36670fe 100644
--- a/src/WindreamHub.Legacy.Client/Routes/AuthenticationRouteService.cs
+++ b/src/WindreamHub.Legacy.Client/Routes/AuthenticationRouteService.cs
@@ -1,6 +1,11 @@
-using Microsoft.Extensions.Options;
+using DigitalData.Core.Legacy.Client;
+using Microsoft.Extensions.Options;
 using System.Net;
 using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
+using WindreamHub.Legacy.Client.Models;
+using WindreamHub.Legacy.Client.Models.Authentication;
 
 namespace WindreamHub.Legacy.Client.Routes
 {
@@ -9,5 +14,10 @@ namespace WindreamHub.Legacy.Client.Routes
         public AuthenticationRouteService(HttpClient client, CookieContainer cookieContainer, IOptions<WindreamClientOptions> clientOptions) : base(client, cookieContainer, clientOptions)
         {
         }
+
+        public async Task<SimplifiedResponse<ValidationResponse, object>> IsValidUser()
+        {
+            return await FetchAsync(route: "/IsValidUser", HttpMethod.Get).ThenAsync(res => res.Simplify<ValidationResponse, object>());
+        }
     }
 }
\ No newline at end of file
diff --git a/src/WindreamHub.Legacy.Client/WindreamClientService.cs b/src/WindreamHub.Legacy.Client/WindreamClientService.cs
index ca16b7d..87181dd 100644
--- a/src/WindreamHub.Legacy.Client/WindreamClientService.cs
+++ b/src/WindreamHub.Legacy.Client/WindreamClientService.cs
@@ -2,6 +2,10 @@
 using Microsoft.Extensions.Options;
 using System.Net;
 using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
+using WindreamHub.Legacy.Client.Models.Authentication;
+using WindreamHub.Legacy.Client.Models;
 using WindreamHub.Legacy.Client.Route;
 using WindreamHub.Legacy.Client.Routes;
 
@@ -23,5 +27,24 @@ namespace WindreamHub.Legacy.Client
         public SystemDetailsRouteService SystemDetails { get; }
 
         public AuthenticationRouteService Authentication { get; }
+
+        public async Task<bool> AuthenticateAsync(ICredential credential)
+        {
+            _client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", credential.AuthorizationHeader);
+            var res = await Authentication.IsValidUser();
+            return res.Ok && res.Data.IsValidUser;
+        }
+
+        public async Task<bool> AuthenticateAsync(string domain, string name, string password)
+        {
+            var uCredential = new UserCredential(domain, name, password);
+            return await AuthenticateAsync(uCredential);
+        }
+
+        public async Task<bool> AuthenticateAsync(string authorizationHeader)
+        {
+            var uCredential = new Base64Credential(authorizationHeader);
+            return await AuthenticateAsync(uCredential);
+        }
     }
 }
\ No newline at end of file
diff --git a/src/WindreamHub.Legacy.Client/WindreamHub.Legacy.Client.csproj b/src/WindreamHub.Legacy.Client/WindreamHub.Legacy.Client.csproj
index 0dcf71b..f652c0d 100644
--- a/src/WindreamHub.Legacy.Client/WindreamHub.Legacy.Client.csproj
+++ b/src/WindreamHub.Legacy.Client/WindreamHub.Legacy.Client.csproj
@@ -83,11 +83,16 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="DIExtensions.cs" />
+    <Compile Include="Models\Authentication\ErrorDetails.cs" />
+    <Compile Include="Models\Authentication\ErrorItem.cs" />
+    <Compile Include="Models\Authentication\ICredential.cs" />
+    <Compile Include="Models\Authentication\ValidationResponse.cs" />
+    <Compile Include="Models\Authentication\Base64Credential.cs" />
     <Compile Include="Models\ModelExtensions.cs" />
     <Compile Include="Models\SimplifiedResponse.cs" />
     <Compile Include="Models\SystemDetails.cs" />
     <Compile Include="Models\SystemDetailsResponse.cs" />
-    <Compile Include="Models\UserCredential.cs" />
+    <Compile Include="Models\Authentication\UserCredential.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Routes\AuthenticationRouteService.cs" />
     <Compile Include="Routes\BaseRouteService.cs" />