initial commit of source

src/Core/Identity/AuthenticatorTokenProvider.cs

@@ -0,0 +1,43 @@
+using System;
+using System.Threading.Tasks;
+using Base32;
+using Microsoft.AspNet.Identity;
+using Bit.Core.Domains;
+using Bit.Core.Enums;
+using OtpSharp;
+
+namespace Bit.Core.Identity
+{
+    public class AuthenticatorTokenProvider : IUserTokenProvider<User>
+    {
+        public Task<bool> CanGenerateTwoFactorTokenAsync(UserManager<User> manager, User user)
+        {
+            var canGenerate = user.TwoFactorEnabled
+                && user.TwoFactorProvider.HasValue
+                && user.TwoFactorProvider.Value == TwoFactorProvider.Authenticator
+                && !string.IsNullOrWhiteSpace(user.AuthenticatorKey);
+
+            return Task.FromResult(canGenerate);
+        }
+
+        public Task<string> GetUserModifierAsync(string purpose, UserManager<User> manager, User user)
+        {
+            return Task.FromResult<string>(null);
+        }
+
+        public Task<string> GenerateAsync(string purpose, UserManager<User> manager, User user)
+        {
+            return Task.FromResult<string>(null);
+        }
+
+        public Task<bool> ValidateAsync(string purpose, string token, UserManager<User> manager, User user)
+        {
+            var otp = new Totp(Base32Encoder.Decode(user.AuthenticatorKey));
+
+            long timeStepMatched;
+            var valid = otp.VerifyTotp(token, out timeStepMatched, new VerificationWindow(2, 2));
+
+            return Task.FromResult(valid);
+        }
+    }
+}