diff --git a/src/Intersvyaz.Core/Intersvyaz.Core.csproj b/src/Intersvyaz.Core/Intersvyaz.Core.csproj
index 108eaa5..1e6ba33 100644
--- a/src/Intersvyaz.Core/Intersvyaz.Core.csproj
+++ b/src/Intersvyaz.Core/Intersvyaz.Core.csproj
@@ -123,6 +123,7 @@
     <Compile Include="Models\SessionData.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Services\ISessionService.cs" />
+    <Compile Include="Services\SessionService.cs" />
     <EmbeddedResource Include="Properties\Intersvyaz.Core.rd.xml" />
   </ItemGroup>
   <ItemGroup>
@@ -130,7 +131,12 @@
       <Version>6.2.8</Version>
     </PackageReference>
   </ItemGroup>
-  <ItemGroup />
+  <ItemGroup>
+    <ProjectReference Include="..\Intersvyaz.Net\Intersvyaz.Net.csproj">
+      <Project>{d53e9b31-82ca-4b3b-a6ba-9f4b9353abb1}</Project>
+      <Name>Intersvyaz.Net</Name>
+    </ProjectReference>
+  </ItemGroup>
   <PropertyGroup Condition=" '$(VisualStudioVersion)' == '' or '$(VisualStudioVersion)' &lt; '14.0' ">
     <VisualStudioVersion>14.0</VisualStudioVersion>
   </PropertyGroup>
diff --git a/src/Intersvyaz.Core/Services/ISessionService.cs b/src/Intersvyaz.Core/Services/ISessionService.cs
index d0e369f..1b8e524 100644
--- a/src/Intersvyaz.Core/Services/ISessionService.cs
+++ b/src/Intersvyaz.Core/Services/ISessionService.cs
@@ -17,17 +17,20 @@ namespace Intersvyaz.Core.Services
         /// <summary>
         /// Получить сессию пользователя.
         /// </summary>
+        /// <param name="username">Имя пользователя.</param>
         /// <returns>Данные об сессии.</returns>
-        SessionData GetSession();
+        SessionData GetSession(string username);
 
         /// <summary>
         /// Проверить, есть ли сессия пользователя.
         /// </summary>
-        bool HasSession();
+        /// <param name="username">Имя пользователя.</param>
+        bool HasSession(string username);
 
         /// <summary>
         /// Удалить сессию пользователя.
         /// </summary>
-        void DeleteSession();
+        /// <param name="username">Имя пользователя.</param>
+        void DeleteSession(string username);
     }
 }
diff --git a/src/Intersvyaz.Core/Services/SessionService.cs b/src/Intersvyaz.Core/Services/SessionService.cs
new file mode 100644
index 0000000..95a3d0d
--- /dev/null
+++ b/src/Intersvyaz.Core/Services/SessionService.cs
@@ -0,0 +1,129 @@
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using System.Globalization;
+using Intersvyaz.Net;
+using Intersvyaz.Core.Models;
+using Windows.Security.Credentials;
+
+namespace Intersvyaz.Core.Services
+{
+    public class SessionService : ISessionService
+    {
+        /// <summary>
+        /// Имя ресурса.
+        /// </summary>
+        private const string RESOURCE_NAME = "Intersvyaz";
+
+        /// <summary>
+        /// Клиент Интерсвязи.
+        /// </summary>
+        private IntersvyazClient _intersvyazClient;
+
+        /// <summary>
+        /// Хранилище паролей.
+        /// </summary>
+        private PasswordVault _passwordVault;
+
+        public SessionService(IntersvyazClient intersvyazClient)
+        {
+            _intersvyazClient = intersvyazClient;
+            _passwordVault = new PasswordVault();
+        }
+
+        /// <inheritdoc />
+        public async Task<SessionData> GetSessionAsync(string username, string password)
+        {
+            try
+            {
+                return GetSession(username);
+            }
+            catch
+            {
+                return await LoginAndSaveSession(username, password);
+            }
+        }
+
+        /// <inheritdoc />
+        public SessionData GetSession(string username)
+        {
+            var passwordCredential = _passwordVault.Retrieve(RESOURCE_NAME, username);
+            return ConvertToSessionData(passwordCredential);
+        }
+
+        /// <inheritdoc />
+        public bool HasSession(string username)
+        {
+            var passwordCredentials = _passwordVault.FindAllByResource(RESOURCE_NAME);
+
+            var count = passwordCredentials
+                .Where(passwordCredential => passwordCredential.UserName == username)
+                .Count();
+            return count > 0;
+        }
+
+        /// <inheritdoc />
+        public void DeleteSession(string username)
+        {
+            var passwordCredential = _passwordVault.Retrieve(RESOURCE_NAME, username);
+            _passwordVault.Remove(passwordCredential);
+        }
+
+        /// <summary>
+        /// Войти в систему и сохранить сессию пользователя.
+        /// </summary>
+        /// <param name="username">Имя пользователя.</param>
+        /// <param name="password">Пароль пользователя.</param>
+        /// <returns>Данные об сессии.</returns>
+        private async Task<SessionData> LoginAndSaveSession(string username, string password)
+        {
+            var responseDto = await _intersvyazClient.Login(username, password);
+
+            var sessionData = new SessionData()
+            {
+                Token = responseDto.Token,
+                ExpiresAt = responseDto.AccessEnd,
+                Username = username,
+            };
+            var passwordCredential = ConvertToPasswordCredential(sessionData);
+
+            _passwordVault.Add(passwordCredential);
+            return sessionData;
+        }
+
+        /// <summary>
+        /// Сконвертировать нативную учетчую запсть в SessionData.
+        /// </summary>
+        /// <param name="passwordCredential">Учетная запись.</param>
+        /// <returns>Данные об сессии.</returns>
+        private SessionData ConvertToSessionData(PasswordCredential passwordCredential)
+        {
+            var entries = passwordCredential.Password.Split(
+                new string[] { ";" }, 2, StringSplitOptions.RemoveEmptyEntries);
+
+            return new SessionData()
+            {
+                Token = entries[0],
+                ExpiresAt = DateTime.Parse(entries[1], CultureInfo.InvariantCulture),
+                Username = passwordCredential.UserName,
+            };
+        }
+
+        /// <summary>
+        /// Сконвертировать SessionData в нативную учетную запись.
+        /// </summary>
+        /// <param name="sessionData">Данные об сессии.</param>
+        /// <returns>Нативная учетная запись.</returns>
+        private PasswordCredential ConvertToPasswordCredential(SessionData sessionData)
+        {
+            var entries = new string[]
+            {
+                sessionData.Token,
+                sessionData.ExpiresAt.ToString(CultureInfo.InvariantCulture),
+            };
+
+            return new PasswordCredential(
+                RESOURCE_NAME, sessionData.Username, string.Join(";", entries));
+        }
+    }
+}