[Tools] Update SendAuthenticationQuery, add new non-anonymous endpoints, and add PutRemoveAuth endpoint (#6786)

* update send api models to support new `email` field

* normalize authentication field evaluation order

* document send response converters

* add FIXME to remove unused constructor argument

* add FIXME to remove unused constructor argument

* introduce `tools-send-email-otp-listing` feature flag

* add `ISendOwnerQuery` to dependency graph

* fix broken tests

* added AuthType prop to send related models with test coverage and debt cleanup

* dotnet format

* add migrations

* dotnet format

* make SendsController null safe (tech debt)

* add AuthType col to Sends table, change Emails col length to 4000, and run migrations

* dotnet format

* update SPs to expect AuthType

* include SP updates in migrations

* remove migrations not intended for merge

* Revert "remove migrations not intended for merge"

This reverts commit 7df56e346a.

undo migrations removal

* extract AuthType inference to util method and remove SQLite file

* fix lints

* address review comments

* fix incorrect assignment and adopt SQL conventions

* fix column assignment order in Send_Update.sql

* remove space added to email list

* assign SQL default value of NULL to AuthType

* update SPs to match migration changes

* remove FF, update SendAuthQuery, and update tests

* new endpoints added but lack test coverage

* dotnet format

* add PutRemoveAuth endpoint with test coverage and tests for new non-anon endpoints

* update RequireFeatureFlag comment for clarity

* respond to Claude's findings

* add additional validation logic to new auth endpoints

* enforce auth policies on individual action methods

* remove JsonConverter directive for AuthType

* remove tools-send-email-otp-listing feature flag

---------

Co-authored-by: ✨ Audrey ✨ <audrey@audreyality.com>
Co-authored-by: ✨ Audrey ✨ <ajensen@bitwarden.com>
Co-authored-by: Daniel James Smith <2670567+djsmith85@users.noreply.github.com>
Co-authored-by: Alex Dragovich <46065570+itsadrago@users.noreply.github.com>

src/Api/Tools/Controllers/SendsController.cs

@@ -5,9 +5,11 @@ using Bit.Api.Tools.Models.Request;
 using Bit.Api.Tools.Models.Response;
 using Bit.Api.Utilities;
 using Bit.Core;
+using Bit.Core.Auth.Identity;
+using Bit.Core.Auth.UserFeatures.SendAccess;
 using Bit.Core.Exceptions;
+using Bit.Core.Platform.Push;
 using Bit.Core.Services;
-using Bit.Core.Settings;
 using Bit.Core.Tools.Enums;
 using Bit.Core.Tools.Models.Data;
 using Bit.Core.Tools.Repositories;
@@ -22,7 +24,6 @@ using Microsoft.AspNetCore.Mvc;
 namespace Bit.Api.Tools.Controllers;
 
 [Route("sends")]
-[Authorize("Application")]
 public class SendsController : Controller
 {
     private readonly ISendRepository _sendRepository;
@@ -31,11 +32,10 @@ public class SendsController : Controller
     private readonly ISendFileStorageService _sendFileStorageService;
     private readonly IAnonymousSendCommand _anonymousSendCommand;
     private readonly INonAnonymousSendCommand _nonAnonymousSendCommand;
-
     private readonly ISendOwnerQuery _sendOwnerQuery;
-
     private readonly ILogger<SendsController> _logger;
-    private readonly GlobalSettings _globalSettings;
+    private readonly IFeatureService _featureService;
+    private readonly IPushNotificationService _pushNotificationService;
 
     public SendsController(
         ISendRepository sendRepository,
@@ -46,7 +46,8 @@ public class SendsController : Controller
         ISendOwnerQuery sendOwnerQuery,
         ISendFileStorageService sendFileStorageService,
         ILogger<SendsController> logger,
-        GlobalSettings globalSettings)
+        IFeatureService featureService,
+        IPushNotificationService pushNotificationService)
     {
         _sendRepository = sendRepository;
         _userService = userService;
@@ -56,10 +57,12 @@ public class SendsController : Controller
         _sendOwnerQuery = sendOwnerQuery;
         _sendFileStorageService = sendFileStorageService;
         _logger = logger;
-        _globalSettings = globalSettings;
+        _featureService = featureService;
+        _pushNotificationService = pushNotificationService;
     }
 
     #region Anonymous endpoints
+
     [AllowAnonymous]
     [HttpPost("access/{id}")]
     public async Task<IActionResult> Access(string id, [FromBody] SendAccessRequestModel model)
@@ -73,21 +76,32 @@ public class SendsController : Controller
 
         var guid = new Guid(CoreHelpers.Base64UrlDecode(id));
         var send = await _sendRepository.GetByIdAsync(guid);
+
         if (send == null)
         {
             throw new BadRequestException("Could not locate send");
         }
+
+        /* This guard can be removed once feature flag is retired*/
+        var sendEmailOtpEnabled = _featureService.IsEnabled(FeatureFlagKeys.SendEmailOTP);
+        if (sendEmailOtpEnabled && send.AuthType == AuthType.Email && send.Emails is not null)
+        {
+            return new UnauthorizedResult();
+        }
+
         var sendAuthResult =
             await _sendAuthorizationService.AccessAsync(send, model.Password);
         if (sendAuthResult.Equals(SendAccessResult.PasswordRequired))
         {
             return new UnauthorizedResult();
         }
+
         if (sendAuthResult.Equals(SendAccessResult.PasswordInvalid))
         {
             await Task.Delay(2000);
             throw new BadRequestException("Invalid password.");
         }
+
         if (sendAuthResult.Equals(SendAccessResult.Denied))
         {
             throw new NotFoundException();
@@ -99,6 +113,7 @@ public class SendsController : Controller
             var creator = await _userService.GetUserByIdAsync(send.UserId.Value);
             sendResponse.CreatorIdentifier = creator.Email;
         }
+
         return new ObjectResult(sendResponse);
     }
 
@@ -122,6 +137,13 @@ public class SendsController : Controller
             throw new BadRequestException("Could not locate send");
         }
 
+        /* This guard can be removed once feature flag is retired*/
+        var sendEmailOtpEnabled = _featureService.IsEnabled(FeatureFlagKeys.SendEmailOTP);
+        if (sendEmailOtpEnabled && send.AuthType == AuthType.Email && send.Emails is not null)
+        {
+            return new UnauthorizedResult();
+        }
+
         var (url, result) = await _anonymousSendCommand.GetSendFileDownloadUrlAsync(send, fileId,
             model.Password);
 
@@ -129,21 +151,19 @@ public class SendsController : Controller
         {
             return new UnauthorizedResult();
         }
+
         if (result.Equals(SendAccessResult.PasswordInvalid))
         {
             await Task.Delay(2000);
             throw new BadRequestException("Invalid password.");
         }
+
         if (result.Equals(SendAccessResult.Denied))
         {
             throw new NotFoundException();
         }
 
-        return new ObjectResult(new SendFileDownloadDataResponseModel()
-        {
-            Id = fileId,
-            Url = url,
-        });
+        return new ObjectResult(new SendFileDownloadDataResponseModel() { Id = fileId, Url = url, });
     }
 
     [AllowAnonymous]
@@ -157,7 +177,8 @@ public class SendsController : Controller
                 {
                     try
                     {
-                        var blobName = eventGridEvent.Subject.Split($"{AzureSendFileStorageService.FilesContainerName}/blobs/")[1];
+                        var blobName =
+                            eventGridEvent.Subject.Split($"{AzureSendFileStorageService.FilesContainerName}/blobs/")[1];
                         var sendId = AzureSendFileStorageService.SendIdFromBlobName(blobName);
                         var send = await _sendRepository.GetByIdAsync(new Guid(sendId));
                         if (send == null)
@@ -166,6 +187,7 @@ public class SendsController : Controller
                             {
                                 await azureSendFileStorageService.DeleteBlobAsync(blobName);
                             }
+
                             return;
                         }
 
@@ -173,7 +195,8 @@ public class SendsController : Controller
                     }
                     catch (Exception e)
                     {
-                        _logger.LogError(e, "Uncaught exception occurred while handling event grid event: {Event}", JsonSerializer.Serialize(eventGridEvent));
+                        _logger.LogError(e, "Uncaught exception occurred while handling event grid event: {Event}",
+                            JsonSerializer.Serialize(eventGridEvent));
                         return;
                     }
                 }
@@ -185,6 +208,7 @@ public class SendsController : Controller
 
     #region Non-anonymous endpoints
 
+    [Authorize(Policies.Application)]
     [HttpGet("{id}")]
     public async Task<SendResponseModel> Get(string id)
     {
@@ -193,6 +217,7 @@ public class SendsController : Controller
         return new SendResponseModel(send);
     }
 
+    [Authorize(Policies.Application)]
     [HttpGet("")]
     public async Task<ListResponseModel<SendResponseModel>> GetAll()
     {
@@ -203,6 +228,67 @@ public class SendsController : Controller
         return result;
     }
 
+    [Authorize(Policy = Policies.Send)]
+    // [RequireFeature(FeatureFlagKeys.SendEmailOTP)]  /* Uncomment once client fallback re-try logic is added */
+    [HttpPost("access/")]
+    public async Task<IActionResult> AccessUsingAuth()
+    {
+        var guid = User.GetSendId();
+        var send = await _sendRepository.GetByIdAsync(guid);
+        if (send == null)
+        {
+            throw new BadRequestException("Could not locate send");
+        }
+        if (send.MaxAccessCount.GetValueOrDefault(int.MaxValue) <= send.AccessCount ||
+            send.ExpirationDate.GetValueOrDefault(DateTime.MaxValue) < DateTime.UtcNow || send.Disabled ||
+            send.DeletionDate < DateTime.UtcNow)
+        {
+            throw new NotFoundException();
+        }
+
+        var sendResponse = new SendAccessResponseModel(send);
+        if (send.UserId.HasValue && !send.HideEmail.GetValueOrDefault())
+        {
+            var creator = await _userService.GetUserByIdAsync(send.UserId.Value);
+            sendResponse.CreatorIdentifier = creator.Email;
+        }
+
+        send.AccessCount++;
+        await _sendRepository.ReplaceAsync(send);
+        await _pushNotificationService.PushSyncSendUpdateAsync(send);
+
+        return new ObjectResult(sendResponse);
+    }
+
+    [Authorize(Policy = Policies.Send)]
+    // [RequireFeature(FeatureFlagKeys.SendEmailOTP)]  /* Uncomment once client fallback re-try logic is added */
+    [HttpPost("access/file/{fileId}")]
+    public async Task<IActionResult> GetSendFileDownloadDataUsingAuth(string fileId)
+    {
+        var sendId = User.GetSendId();
+        var send = await _sendRepository.GetByIdAsync(sendId);
+
+        if (send == null)
+        {
+            throw new BadRequestException("Could not locate send");
+        }
+        if (send.MaxAccessCount.GetValueOrDefault(int.MaxValue) <= send.AccessCount ||
+            send.ExpirationDate.GetValueOrDefault(DateTime.MaxValue) < DateTime.UtcNow || send.Disabled ||
+            send.DeletionDate < DateTime.UtcNow)
+        {
+            throw new NotFoundException();
+        }
+
+        var url = await _sendFileStorageService.GetSendFileDownloadUrlAsync(send, fileId);
+
+        send.AccessCount++;
+        await _sendRepository.ReplaceAsync(send);
+        await _pushNotificationService.PushSyncSendUpdateAsync(send);
+
+        return new ObjectResult(new SendFileDownloadDataResponseModel() { Id = fileId, Url = url });
+    }
+
+    [Authorize(Policies.Application)]
     [HttpPost("")]
     public async Task<SendResponseModel> Post([FromBody] SendRequestModel model)
     {
@@ -213,6 +299,7 @@ public class SendsController : Controller
         return new SendResponseModel(send);
     }
 
+    [Authorize(Policies.Application)]
     [HttpPost("file/v2")]
     public async Task<SendFileUploadDataResponseModel> PostFile([FromBody] SendRequestModel model)
     {
@@ -243,6 +330,7 @@ public class SendsController : Controller
         };
     }
 
+    [Authorize(Policies.Application)]
     [HttpGet("{id}/file/{fileId}")]
     public async Task<SendFileUploadDataResponseModel> RenewFileUpload(string id, string fileId)
     {
@@ -267,6 +355,7 @@ public class SendsController : Controller
         };
     }
 
+    [Authorize(Policies.Application)]
     [HttpPost("{id}/file/{fileId}")]
     [SelfHosted(SelfHostedOnly = true)]
     [RequestSizeLimit(Constants.FileSize501mb)]
@@ -283,12 +372,14 @@ public class SendsController : Controller
         {
             throw new BadRequestException("Could not locate send");
         }
+
         await Request.GetFileAsync(async (stream) =>
         {
             await _nonAnonymousSendCommand.UploadFileToExistingSendAsync(stream, send);
         });
     }
 
+    [Authorize(Policies.Application)]
     [HttpPut("{id}")]
     public async Task<SendResponseModel> Put(string id, [FromBody] SendRequestModel model)
     {
@@ -304,6 +395,7 @@ public class SendsController : Controller
         return new SendResponseModel(send);
     }
 
+    [Authorize(Policies.Application)]
     [HttpPut("{id}/remove-password")]
     public async Task<SendResponseModel> PutRemovePassword(string id)
     {
@@ -322,6 +414,28 @@ public class SendsController : Controller
         return new SendResponseModel(send);
     }
 
+    // Removes ALL authentication (email or password) if any is present
+    [Authorize(Policies.Application)]
+    [HttpPut("{id}/remove-auth")]
+    public async Task<SendResponseModel> PutRemoveAuth(string id)
+    {
+        var userId = _userService.GetProperUserId(User) ?? throw new InvalidOperationException("User ID not found");
+        var send = await _sendRepository.GetByIdAsync(new Guid(id));
+        if (send == null || send.UserId != userId)
+        {
+            throw new NotFoundException();
+        }
+
+        // This endpoint exists because PUT preserves existing Password/Emails when not provided.
+        // This allows clients to update other fields without re-submitting sensitive auth data.
+        send.Password = null;
+        send.Emails = null;
+        send.AuthType = AuthType.None;
+        await _nonAnonymousSendCommand.SaveSendAsync(send);
+        return new SendResponseModel(send);
+    }
+
+    [Authorize(Policies.Application)]
     [HttpDelete("{id}")]
     public async Task Delete(string id)
     {

src/Core/Constants.cs

@@ -235,16 +235,6 @@ public static class FeatureFlagKeys
     public const string SendUIRefresh = "pm-28175-send-ui-refresh";
     public const string SendEmailOTP = "pm-19051-send-email-verification";
 
-    /// <summary>
-    /// Enable this flag to output email/OTP authenticated sends from the `GET sends` endpoint. When
-    /// this flag is disabled, the `GET sends` endpoint omits email/OTP authenticated sends.
-    /// </summary>
-    /// <remarks>
-    /// This flag is server-side only, and only inhibits the endpoint returning all sends.
-    /// Email/OTP sends can still be created and downloaded through other endpoints.
-    /// </remarks>
-    public const string PM19051_ListEmailOtpSends = "tools-send-email-otp-listing";
-
     /* Vault Team */
     public const string CipherKeyEncryption = "cipher-key-encryption";
     public const string PM19941MigrateCipherDomainToSdk = "pm-19941-migrate-cipher-domain-to-sdk";

src/Core/Tools/Enums/AuthType.cs

@@ -1,11 +1,8 @@
-using System.Text.Json.Serialization;
-
-namespace Bit.Core.Tools.Enums;
+namespace Bit.Core.Tools.Enums;
 
 /// <summary>
 /// Specifies the authentication method required to access a Send.
 /// </summary>
-[JsonConverter(typeof(JsonStringEnumConverter))]
 public enum AuthType : byte
 {
     /// <summary>

src/Core/Tools/SendFeatures/Queries/SendAuthenticationQuery.cs

@@ -1,4 +1,5 @@
-using Bit.Core.Tools.Models.Data;
+using Bit.Core.Tools.Enums;
+using Bit.Core.Tools.Models.Data;
 using Bit.Core.Tools.Repositories;
 using Bit.Core.Tools.SendFeatures.Queries.Interfaces;
 
@@ -37,8 +38,8 @@ public class SendAuthenticationQuery : ISendAuthenticationQuery
         {
             null => NEVER_AUTHENTICATE,
             var s when s.AccessCount >= s.MaxAccessCount => NEVER_AUTHENTICATE,
-            var s when s.Emails is not null => emailOtp(s.Emails),
-            var s when s.Password is not null => new ResourcePassword(s.Password),
+            var s when s.AuthType == AuthType.Email && s.Emails is not null => emailOtp(s.Emails),
+            var s when s.AuthType == AuthType.Password && s.Password is not null => new ResourcePassword(s.Password),
             _ => NOT_AUTHENTICATED
         };
 

src/Core/Tools/SendFeatures/Queries/SendOwnerQuery.cs

@@ -12,7 +12,6 @@ namespace Bit.Core.Tools.SendFeatures.Queries;
 public class SendOwnerQuery : ISendOwnerQuery
 {
     private readonly ISendRepository _repository;
-    private readonly IFeatureService _features;
     private readonly IUserService _users;
 
     /// <summary>
@@ -24,10 +23,9 @@ public class SendOwnerQuery : ISendOwnerQuery
     /// <exception cref="ArgumentNullException">
     /// Thrown when <paramref name="sendRepository"/> is <see langword="null"/>.
     /// </exception>
-    public SendOwnerQuery(ISendRepository sendRepository, IFeatureService features, IUserService users)
+    public SendOwnerQuery(ISendRepository sendRepository, IUserService users)
     {
         _repository = sendRepository;
-        _features = features ?? throw new ArgumentNullException(nameof(features));
         _users = users ?? throw new ArgumentNullException(nameof(users));
     }
 
@@ -51,16 +49,6 @@ public class SendOwnerQuery : ISendOwnerQuery
         var userId = _users.GetProperUserId(user) ?? throw new BadRequestException("invalid user.");
         var sends = await _repository.GetManyByUserIdAsync(userId);
 
-        var removeEmailOtp = !_features.IsEnabled(FeatureFlagKeys.PM19051_ListEmailOtpSends);
-        if (removeEmailOtp)
-        {
-            // reify list to avoid invalidating the enumerator
-            foreach (var s in sends.Where(s => s.Emails != null).ToList())
-            {
-                sends.Remove(s);
-            }
-        }
-
         return sends;
     }
 }

test/Api.Test/Tools/Controllers/SendsControllerTests.cs

@@ -8,8 +8,8 @@ using Bit.Api.Tools.Models.Request;
 using Bit.Api.Tools.Models.Response;
 using Bit.Core.Entities;
 using Bit.Core.Exceptions;
+using Bit.Core.Platform.Push;
 using Bit.Core.Services;
-using Bit.Core.Settings;
 using Bit.Core.Tools.Entities;
 using Bit.Core.Tools.Enums;
 using Bit.Core.Tools.Models.Data;
@@ -28,7 +28,6 @@ namespace Bit.Api.Test.Tools.Controllers;
 public class SendsControllerTests : IDisposable
 {
     private readonly SendsController _sut;
-    private readonly GlobalSettings _globalSettings;
     private readonly IUserService _userService;
     private readonly ISendRepository _sendRepository;
     private readonly INonAnonymousSendCommand _nonAnonymousSendCommand;
@@ -37,6 +36,8 @@ public class SendsControllerTests : IDisposable
     private readonly ISendAuthorizationService _sendAuthorizationService;
     private readonly ISendFileStorageService _sendFileStorageService;
     private readonly ILogger<SendsController> _logger;
+    private readonly IFeatureService _featureService;
+    private readonly IPushNotificationService _pushNotificationService;
 
     public SendsControllerTests()
     {
@@ -47,8 +48,9 @@ public class SendsControllerTests : IDisposable
         _sendOwnerQuery = Substitute.For<ISendOwnerQuery>();
         _sendAuthorizationService = Substitute.For<ISendAuthorizationService>();
         _sendFileStorageService = Substitute.For<ISendFileStorageService>();
-        _globalSettings = new GlobalSettings();
         _logger = Substitute.For<ILogger<SendsController>>();
+        _featureService = Substitute.For<IFeatureService>();
+        _pushNotificationService = Substitute.For<IPushNotificationService>();
 
         _sut = new SendsController(
             _sendRepository,
@@ -59,7 +61,8 @@ public class SendsControllerTests : IDisposable
             _sendOwnerQuery,
             _sendFileStorageService,
             _logger,
-            _globalSettings
+            _featureService,
+            _pushNotificationService
         );
     }
 
@@ -96,8 +99,8 @@ public class SendsControllerTests : IDisposable
     {
         var now = DateTime.UtcNow;
         var expected = "You cannot have a Send with a deletion date that far " +
-                    "into the future. Adjust the Deletion Date to a value less than 31 days from now " +
-                    "and try again.";
+                       "into the future. Adjust the Deletion Date to a value less than 31 days from now " +
+                       "and try again.";
         var request = new SendRequestModel() { DeletionDate = now.AddDays(32) };
 
         var exception = await Assert.ThrowsAsync<BadRequestException>(() => _sut.Post(request));
@@ -109,9 +112,10 @@ public class SendsControllerTests : IDisposable
     {
         var now = DateTime.UtcNow;
         var expected = "You cannot have a Send with a deletion date that far " +
-                    "into the future. Adjust the Deletion Date to a value less than 31 days from now " +
-                    "and try again.";
-        var request = new SendRequestModel() { Type = SendType.File, FileLength = 1024L, DeletionDate = now.AddDays(32) };
+                       "into the future. Adjust the Deletion Date to a value less than 31 days from now " +
+                       "and try again.";
+        var request =
+            new SendRequestModel() { Type = SendType.File, FileLength = 1024L, DeletionDate = now.AddDays(32) };
 
         var exception = await Assert.ThrowsAsync<BadRequestException>(() => _sut.PostFile(request));
         Assert.Equal(expected, exception.Message);
@@ -409,7 +413,8 @@ public class SendsControllerTests : IDisposable
     }
 
     [Theory, AutoData]
-    public async Task PutRemovePassword_WithWrongUser_ThrowsNotFoundException(Guid userId, Guid otherUserId, Guid sendId)
+    public async Task PutRemovePassword_WithWrongUser_ThrowsNotFoundException(Guid userId, Guid otherUserId,
+        Guid sendId)
     {
         _userService.GetProperUserId(Arg.Any<ClaimsPrincipal>()).Returns(userId);
         var existingSend = new Send
@@ -753,4 +758,683 @@ public class SendsControllerTests : IDisposable
             s.Password == null &&
             s.Emails == null));
     }
+
+    #region Authenticated Access Endpoints
+
+    [Theory, AutoData]
+    public async Task AccessUsingAuth_WithValidSend_ReturnsSendAccessResponse(Guid sendId, User creator)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            UserId = creator.Id,
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            HideEmail = false,
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = null,
+            Disabled = false,
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+        _userService.GetUserByIdAsync(creator.Id).Returns(creator);
+
+        var result = await _sut.AccessUsingAuth();
+
+        Assert.NotNull(result);
+        var objectResult = Assert.IsType<ObjectResult>(result);
+        var response = Assert.IsType<SendAccessResponseModel>(objectResult.Value);
+        Assert.Equal(CoreHelpers.Base64UrlEncode(sendId.ToByteArray()), response.Id);
+        Assert.Equal(creator.Email, response.CreatorIdentifier);
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+        await _userService.Received(1).GetUserByIdAsync(creator.Id);
+    }
+
+    [Theory, AutoData]
+    public async Task AccessUsingAuth_WithHideEmail_DoesNotIncludeCreatorIdentifier(Guid sendId, User creator)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            UserId = creator.Id,
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            HideEmail = true,
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = null,
+            Disabled = false,
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+
+        var result = await _sut.AccessUsingAuth();
+
+        Assert.NotNull(result);
+        var objectResult = Assert.IsType<ObjectResult>(result);
+        var response = Assert.IsType<SendAccessResponseModel>(objectResult.Value);
+        Assert.Equal(CoreHelpers.Base64UrlEncode(sendId.ToByteArray()), response.Id);
+        Assert.Null(response.CreatorIdentifier);
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+        await _userService.DidNotReceive().GetUserByIdAsync(Arg.Any<Guid>());
+    }
+
+    [Theory, AutoData]
+    public async Task AccessUsingAuth_WithNoUserId_DoesNotIncludeCreatorIdentifier(Guid sendId)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            UserId = null,
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            HideEmail = false,
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = null,
+            Disabled = false,
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+
+        var result = await _sut.AccessUsingAuth();
+
+        Assert.NotNull(result);
+        var objectResult = Assert.IsType<ObjectResult>(result);
+        var response = Assert.IsType<SendAccessResponseModel>(objectResult.Value);
+        Assert.Equal(CoreHelpers.Base64UrlEncode(sendId.ToByteArray()), response.Id);
+        Assert.Null(response.CreatorIdentifier);
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+        await _userService.DidNotReceive().GetUserByIdAsync(Arg.Any<Guid>());
+    }
+
+    [Theory, AutoData]
+    public async Task AccessUsingAuth_WithNonExistentSend_ThrowsBadRequestException(Guid sendId)
+    {
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns((Send)null);
+
+        var exception =
+            await Assert.ThrowsAsync<BadRequestException>(() => _sut.AccessUsingAuth());
+
+        Assert.Equal("Could not locate send", exception.Message);
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+    }
+
+    [Theory, AutoData]
+    public async Task AccessUsingAuth_WithFileSend_ReturnsCorrectResponse(Guid sendId, User creator)
+    {
+        var fileData = new SendFileData("Test File", "Notes", "document.pdf") { Id = "file-123", Size = 2048 };
+        var send = new Send
+        {
+            Id = sendId,
+            UserId = creator.Id,
+            Type = SendType.File,
+            Data = JsonSerializer.Serialize(fileData),
+            HideEmail = false,
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = null,
+            Disabled = false,
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+        _userService.GetUserByIdAsync(creator.Id).Returns(creator);
+
+        var result = await _sut.AccessUsingAuth();
+
+        Assert.NotNull(result);
+        var objectResult = Assert.IsType<ObjectResult>(result);
+        var response = Assert.IsType<SendAccessResponseModel>(objectResult.Value);
+        Assert.Equal(CoreHelpers.Base64UrlEncode(sendId.ToByteArray()), response.Id);
+        Assert.Equal(SendType.File, response.Type);
+        Assert.NotNull(response.File);
+        Assert.Equal("file-123", response.File.Id);
+        Assert.Equal(creator.Email, response.CreatorIdentifier);
+    }
+
+    [Theory, AutoData]
+    public async Task GetSendFileDownloadDataUsingAuth_WithValidFileId_ReturnsDownloadUrl(
+        Guid sendId, string fileId, string expectedUrl)
+    {
+        var fileData = new SendFileData("Test File", "Notes", "document.pdf") { Id = fileId, Size = 2048 };
+        var send = new Send
+        {
+            Id = sendId,
+            Type = SendType.File,
+            Data = JsonSerializer.Serialize(fileData),
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = null,
+            Disabled = false,
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+        _sendFileStorageService.GetSendFileDownloadUrlAsync(send, fileId).Returns(expectedUrl);
+
+        var result = await _sut.GetSendFileDownloadDataUsingAuth(fileId);
+
+        Assert.NotNull(result);
+        var objectResult = Assert.IsType<ObjectResult>(result);
+        var response = Assert.IsType<SendFileDownloadDataResponseModel>(objectResult.Value);
+        Assert.Equal(fileId, response.Id);
+        Assert.Equal(expectedUrl, response.Url);
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+        await _sendFileStorageService.Received(1).GetSendFileDownloadUrlAsync(send, fileId);
+    }
+
+    [Theory, AutoData]
+    public async Task GetSendFileDownloadDataUsingAuth_WithNonExistentSend_ThrowsBadRequestException(
+        Guid sendId, string fileId)
+    {
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns((Send)null);
+
+        var exception =
+            await Assert.ThrowsAsync<BadRequestException>(() => _sut.GetSendFileDownloadDataUsingAuth(fileId));
+
+        Assert.Equal("Could not locate send", exception.Message);
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+        await _sendFileStorageService.DidNotReceive()
+            .GetSendFileDownloadUrlAsync(Arg.Any<Send>(), Arg.Any<string>());
+    }
+
+    [Theory, AutoData]
+    public async Task GetSendFileDownloadDataUsingAuth_WithTextSend_StillReturnsResponse(
+        Guid sendId, string fileId, string expectedUrl)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = null,
+            Disabled = false,
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+        _sendFileStorageService.GetSendFileDownloadUrlAsync(send, fileId).Returns(expectedUrl);
+
+        var result = await _sut.GetSendFileDownloadDataUsingAuth(fileId);
+
+        Assert.NotNull(result);
+        var objectResult = Assert.IsType<ObjectResult>(result);
+        var response = Assert.IsType<SendFileDownloadDataResponseModel>(objectResult.Value);
+        Assert.Equal(fileId, response.Id);
+        Assert.Equal(expectedUrl, response.Url);
+    }
+
+    #region AccessUsingAuth Validation Tests
+
+    [Theory, AutoData]
+    public async Task AccessUsingAuth_WithExpiredSend_ThrowsNotFoundException(Guid sendId)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            UserId = Guid.NewGuid(),
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = DateTime.UtcNow.AddDays(-1), // Expired yesterday
+            Disabled = false,
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+
+        await Assert.ThrowsAsync<NotFoundException>(() => _sut.AccessUsingAuth());
+
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+    }
+
+    [Theory, AutoData]
+    public async Task AccessUsingAuth_WithDeletedSend_ThrowsNotFoundException(Guid sendId)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            UserId = Guid.NewGuid(),
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            DeletionDate = DateTime.UtcNow.AddDays(-1), // Should have been deleted yesterday
+            ExpirationDate = null,
+            Disabled = false,
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+
+        await Assert.ThrowsAsync<NotFoundException>(() => _sut.AccessUsingAuth());
+
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+    }
+
+    [Theory, AutoData]
+    public async Task AccessUsingAuth_WithDisabledSend_ThrowsNotFoundException(Guid sendId)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            UserId = Guid.NewGuid(),
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = null,
+            Disabled = true, // Disabled
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+
+        await Assert.ThrowsAsync<NotFoundException>(() => _sut.AccessUsingAuth());
+
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+    }
+
+    [Theory, AutoData]
+    public async Task AccessUsingAuth_WithAccessCountExceeded_ThrowsNotFoundException(Guid sendId)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            UserId = Guid.NewGuid(),
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = null,
+            Disabled = false,
+            AccessCount = 5,
+            MaxAccessCount = 5 // Limit reached
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+
+        await Assert.ThrowsAsync<NotFoundException>(() => _sut.AccessUsingAuth());
+
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+    }
+
+    #endregion
+
+    #region GetSendFileDownloadDataUsingAuth Validation Tests
+
+    [Theory, AutoData]
+    public async Task GetSendFileDownloadDataUsingAuth_WithExpiredSend_ThrowsNotFoundException(
+        Guid sendId, string fileId)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            Type = SendType.File,
+            Data = JsonSerializer.Serialize(new SendFileData("Test", "Notes", "file.pdf")),
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = DateTime.UtcNow.AddDays(-1), // Expired
+            Disabled = false,
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+
+        await Assert.ThrowsAsync<NotFoundException>(() => _sut.GetSendFileDownloadDataUsingAuth(fileId));
+
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+    }
+
+    [Theory, AutoData]
+    public async Task GetSendFileDownloadDataUsingAuth_WithDeletedSend_ThrowsNotFoundException(
+        Guid sendId, string fileId)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            Type = SendType.File,
+            Data = JsonSerializer.Serialize(new SendFileData("Test", "Notes", "file.pdf")),
+            DeletionDate = DateTime.UtcNow.AddDays(-1), // Deleted
+            ExpirationDate = null,
+            Disabled = false,
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+
+        await Assert.ThrowsAsync<NotFoundException>(() => _sut.GetSendFileDownloadDataUsingAuth(fileId));
+
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+    }
+
+    [Theory, AutoData]
+    public async Task GetSendFileDownloadDataUsingAuth_WithDisabledSend_ThrowsNotFoundException(
+        Guid sendId, string fileId)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            Type = SendType.File,
+            Data = JsonSerializer.Serialize(new SendFileData("Test", "Notes", "file.pdf")),
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = null,
+            Disabled = true, // Disabled
+            AccessCount = 0,
+            MaxAccessCount = null
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+
+        await Assert.ThrowsAsync<NotFoundException>(() => _sut.GetSendFileDownloadDataUsingAuth(fileId));
+
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+    }
+
+    [Theory, AutoData]
+    public async Task GetSendFileDownloadDataUsingAuth_WithAccessCountExceeded_ThrowsNotFoundException(
+        Guid sendId, string fileId)
+    {
+        var send = new Send
+        {
+            Id = sendId,
+            Type = SendType.File,
+            Data = JsonSerializer.Serialize(new SendFileData("Test", "Notes", "file.pdf")),
+            DeletionDate = DateTime.UtcNow.AddDays(7),
+            ExpirationDate = null,
+            Disabled = false,
+            AccessCount = 10,
+            MaxAccessCount = 10 // Limit reached
+        };
+        var user = CreateUserWithSendIdClaim(sendId);
+        _sut.ControllerContext = CreateControllerContextWithUser(user);
+        _sendRepository.GetByIdAsync(sendId).Returns(send);
+
+        await Assert.ThrowsAsync<NotFoundException>(() => _sut.GetSendFileDownloadDataUsingAuth(fileId));
+
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+    }
+
+    #endregion
+
+    #endregion
+
+    #region PutRemoveAuth Tests
+
+    [Theory, AutoData]
+    public async Task PutRemoveAuth_WithPasswordProtectedSend_RemovesPasswordAndSetsAuthTypeNone(Guid userId,
+        Guid sendId)
+    {
+        _userService.GetProperUserId(Arg.Any<ClaimsPrincipal>()).Returns(userId);
+        var existingSend = new Send
+        {
+            Id = sendId,
+            UserId = userId,
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            Password = "hashed-password",
+            Emails = null,
+            AuthType = AuthType.Password
+        };
+        _sendRepository.GetByIdAsync(sendId).Returns(existingSend);
+
+        var result = await _sut.PutRemoveAuth(sendId.ToString());
+
+        Assert.NotNull(result);
+        Assert.Equal(sendId, result.Id);
+        Assert.Equal(AuthType.None, result.AuthType);
+        Assert.Null(result.Password);
+        Assert.Null(result.Emails);
+        await _nonAnonymousSendCommand.Received(1).SaveSendAsync(Arg.Is<Send>(s =>
+            s.Id == sendId &&
+            s.Password == null &&
+            s.Emails == null &&
+            s.AuthType == AuthType.None));
+    }
+
+    [Theory, AutoData]
+    public async Task PutRemoveAuth_WithEmailProtectedSend_RemovesEmailsAndSetsAuthTypeNone(Guid userId, Guid sendId)
+    {
+        _userService.GetProperUserId(Arg.Any<ClaimsPrincipal>()).Returns(userId);
+        var existingSend = new Send
+        {
+            Id = sendId,
+            UserId = userId,
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            Password = null,
+            Emails = "test@example.com,user@example.com",
+            AuthType = AuthType.Email
+        };
+        _sendRepository.GetByIdAsync(sendId).Returns(existingSend);
+
+        var result = await _sut.PutRemoveAuth(sendId.ToString());
+
+        Assert.NotNull(result);
+        Assert.Equal(sendId, result.Id);
+        Assert.Equal(AuthType.None, result.AuthType);
+        Assert.Null(result.Password);
+        Assert.Null(result.Emails);
+        await _nonAnonymousSendCommand.Received(1).SaveSendAsync(Arg.Is<Send>(s =>
+            s.Id == sendId &&
+            s.Password == null &&
+            s.Emails == null &&
+            s.AuthType == AuthType.None));
+    }
+
+    [Theory, AutoData]
+    public async Task PutRemoveAuth_WithSendAlreadyHavingNoAuth_StillSucceeds(Guid userId, Guid sendId)
+    {
+        _userService.GetProperUserId(Arg.Any<ClaimsPrincipal>()).Returns(userId);
+        var existingSend = new Send
+        {
+            Id = sendId,
+            UserId = userId,
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            Password = null,
+            Emails = null,
+            AuthType = AuthType.None
+        };
+        _sendRepository.GetByIdAsync(sendId).Returns(existingSend);
+
+        var result = await _sut.PutRemoveAuth(sendId.ToString());
+
+        Assert.NotNull(result);
+        Assert.Equal(sendId, result.Id);
+        Assert.Equal(AuthType.None, result.AuthType);
+        Assert.Null(result.Password);
+        Assert.Null(result.Emails);
+        await _nonAnonymousSendCommand.Received(1).SaveSendAsync(Arg.Is<Send>(s =>
+            s.Id == sendId &&
+            s.Password == null &&
+            s.Emails == null &&
+            s.AuthType == AuthType.None));
+    }
+
+    [Theory, AutoData]
+    public async Task PutRemoveAuth_WithFileSend_RemovesAuthAndPreservesFileData(Guid userId, Guid sendId)
+    {
+        _userService.GetProperUserId(Arg.Any<ClaimsPrincipal>()).Returns(userId);
+        var fileData = new SendFileData("Test File", "Notes", "document.pdf") { Id = "file-123", Size = 2048 };
+        var existingSend = new Send
+        {
+            Id = sendId,
+            UserId = userId,
+            Type = SendType.File,
+            Data = JsonSerializer.Serialize(fileData),
+            Password = "hashed-password",
+            Emails = null,
+            AuthType = AuthType.Password
+        };
+        _sendRepository.GetByIdAsync(sendId).Returns(existingSend);
+
+        var result = await _sut.PutRemoveAuth(sendId.ToString());
+
+        Assert.NotNull(result);
+        Assert.Equal(sendId, result.Id);
+        Assert.Equal(AuthType.None, result.AuthType);
+        Assert.Equal(SendType.File, result.Type);
+        Assert.NotNull(result.File);
+        Assert.Equal("file-123", result.File.Id);
+        Assert.Null(result.Password);
+        Assert.Null(result.Emails);
+    }
+
+    [Theory, AutoData]
+    public async Task PutRemoveAuth_WithNonExistentSend_ThrowsNotFoundException(Guid userId, Guid sendId)
+    {
+        _userService.GetProperUserId(Arg.Any<ClaimsPrincipal>()).Returns(userId);
+        _sendRepository.GetByIdAsync(sendId).Returns((Send)null);
+
+        await Assert.ThrowsAsync<NotFoundException>(() => _sut.PutRemoveAuth(sendId.ToString()));
+
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+        await _nonAnonymousSendCommand.DidNotReceive().SaveSendAsync(Arg.Any<Send>());
+    }
+
+    [Theory, AutoData]
+    public async Task PutRemoveAuth_WithWrongUser_ThrowsNotFoundException(Guid userId, Guid otherUserId, Guid sendId)
+    {
+        _userService.GetProperUserId(Arg.Any<ClaimsPrincipal>()).Returns(userId);
+        var existingSend = new Send
+        {
+            Id = sendId,
+            UserId = otherUserId,
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            Password = "hashed-password",
+            AuthType = AuthType.Password
+        };
+        _sendRepository.GetByIdAsync(sendId).Returns(existingSend);
+
+        await Assert.ThrowsAsync<NotFoundException>(() => _sut.PutRemoveAuth(sendId.ToString()));
+
+        await _sendRepository.Received(1).GetByIdAsync(sendId);
+        await _nonAnonymousSendCommand.DidNotReceive().SaveSendAsync(Arg.Any<Send>());
+    }
+
+    [Theory, AutoData]
+    public async Task PutRemoveAuth_WithNullUserId_ThrowsInvalidOperationException(Guid sendId)
+    {
+        _userService.GetProperUserId(Arg.Any<ClaimsPrincipal>()).Returns((Guid?)null);
+
+        var exception =
+            await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.PutRemoveAuth(sendId.ToString()));
+
+        Assert.Equal("User ID not found", exception.Message);
+        await _sendRepository.DidNotReceive().GetByIdAsync(Arg.Any<Guid>());
+        await _nonAnonymousSendCommand.DidNotReceive().SaveSendAsync(Arg.Any<Send>());
+    }
+
+    [Theory, AutoData]
+    public async Task PutRemoveAuth_WithSendHavingBothPasswordAndEmails_RemovesBoth(Guid userId, Guid sendId)
+    {
+        _userService.GetProperUserId(Arg.Any<ClaimsPrincipal>()).Returns(userId);
+        var existingSend = new Send
+        {
+            Id = sendId,
+            UserId = userId,
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            Password = "hashed-password",
+            Emails = "test@example.com",
+            AuthType = AuthType.Password
+        };
+        _sendRepository.GetByIdAsync(sendId).Returns(existingSend);
+
+        var result = await _sut.PutRemoveAuth(sendId.ToString());
+
+        Assert.NotNull(result);
+        Assert.Equal(sendId, result.Id);
+        Assert.Equal(AuthType.None, result.AuthType);
+        Assert.Null(result.Password);
+        Assert.Null(result.Emails);
+        await _nonAnonymousSendCommand.Received(1).SaveSendAsync(Arg.Is<Send>(s =>
+            s.Id == sendId &&
+            s.Password == null &&
+            s.Emails == null &&
+            s.AuthType == AuthType.None));
+    }
+
+    [Theory, AutoData]
+    public async Task PutRemoveAuth_PreservesOtherSendProperties(Guid userId, Guid sendId)
+    {
+        _userService.GetProperUserId(Arg.Any<ClaimsPrincipal>()).Returns(userId);
+        var deletionDate = DateTime.UtcNow.AddDays(7);
+        var expirationDate = DateTime.UtcNow.AddDays(3);
+        var existingSend = new Send
+        {
+            Id = sendId,
+            UserId = userId,
+            Type = SendType.Text,
+            Data = JsonSerializer.Serialize(new SendTextData("Test", "Notes", "Text", false)),
+            Password = "hashed-password",
+            AuthType = AuthType.Password,
+            Key = "encryption-key",
+            MaxAccessCount = 10,
+            AccessCount = 3,
+            DeletionDate = deletionDate,
+            ExpirationDate = expirationDate,
+            Disabled = false,
+            HideEmail = true
+        };
+        _sendRepository.GetByIdAsync(sendId).Returns(existingSend);
+
+        var result = await _sut.PutRemoveAuth(sendId.ToString());
+
+        Assert.NotNull(result);
+        Assert.Equal(sendId, result.Id);
+        Assert.Equal(AuthType.None, result.AuthType);
+        // Verify other properties are preserved
+        Assert.Equal("encryption-key", result.Key);
+        Assert.Equal(10, result.MaxAccessCount);
+        Assert.Equal(3, result.AccessCount);
+        Assert.Equal(deletionDate, result.DeletionDate);
+        Assert.Equal(expirationDate, result.ExpirationDate);
+        Assert.False(result.Disabled);
+        Assert.True(result.HideEmail);
+    }
+
+    #endregion
+
+    #region Test Helpers
+
+    private static ClaimsPrincipal CreateUserWithSendIdClaim(Guid sendId)
+    {
+        var claims = new List<Claim> { new Claim("send_id", sendId.ToString()) };
+        var identity = new ClaimsIdentity(claims, "TestAuth");
+        return new ClaimsPrincipal(identity);
+    }
+
+    private static ControllerContext CreateControllerContextWithUser(ClaimsPrincipal user)
+    {
+        return new ControllerContext { HttpContext = new Microsoft.AspNetCore.Http.DefaultHttpContext { User = user } };
+    }
+
+    #endregion
 }

test/Core.Test/Tools/Services/SendAuthenticationQueryTests.cs

@@ -1,4 +1,5 @@
 using Bit.Core.Tools.Entities;
+using Bit.Core.Tools.Enums;
 using Bit.Core.Tools.Models.Data;
 using Bit.Core.Tools.Repositories;
 using Bit.Core.Tools.SendFeatures.Queries;
@@ -47,7 +48,7 @@ public class SendAuthenticationQueryTests
     {
         // Arrange
         var sendId = Guid.NewGuid();
-        var send = CreateSend(accessCount: 0, maxAccessCount: 10, emails: emailString, password: null);
+        var send = CreateSend(accessCount: 0, maxAccessCount: 10, emails: emailString, password: null, AuthType.Email);
         _sendRepository.GetByIdAsync(sendId).Returns(send);
 
         // Act
@@ -63,7 +64,7 @@ public class SendAuthenticationQueryTests
     {
         // Arrange
         var sendId = Guid.NewGuid();
-        var send = CreateSend(accessCount: 0, maxAccessCount: 10, emails: "test@example.com", password: "hashedpassword");
+        var send = CreateSend(accessCount: 0, maxAccessCount: 10, emails: "test@example.com", password: "hashedpassword", AuthType.Email);
         _sendRepository.GetByIdAsync(sendId).Returns(send);
 
         // Act
@@ -78,7 +79,7 @@ public class SendAuthenticationQueryTests
     {
         // Arrange
         var sendId = Guid.NewGuid();
-        var send = CreateSend(accessCount: 0, maxAccessCount: 10, emails: null, password: null);
+        var send = CreateSend(accessCount: 0, maxAccessCount: 10, emails: null, password: null, AuthType.None);
         _sendRepository.GetByIdAsync(sendId).Returns(send);
 
         // Act
@@ -105,11 +106,11 @@ public class SendAuthenticationQueryTests
     public static IEnumerable<object[]> AuthenticationMethodTestCases()
     {
         yield return new object[] { null, typeof(NeverAuthenticate) };
-        yield return new object[] { CreateSend(accessCount: 5, maxAccessCount: 5, emails: null, password: null), typeof(NeverAuthenticate) };
-        yield return new object[] { CreateSend(accessCount: 6, maxAccessCount: 5, emails: null, password: null), typeof(NeverAuthenticate) };
-        yield return new object[] { CreateSend(accessCount: 0, maxAccessCount: 10, emails: "test@example.com", password: null), typeof(EmailOtp) };
-        yield return new object[] { CreateSend(accessCount: 0, maxAccessCount: 10, emails: null, password: "hashedpassword"), typeof(ResourcePassword) };
-        yield return new object[] { CreateSend(accessCount: 0, maxAccessCount: 10, emails: null, password: null), typeof(NotAuthenticated) };
+        yield return new object[] { CreateSend(accessCount: 5, maxAccessCount: 5, emails: null, password: null, AuthType.None), typeof(NeverAuthenticate) };
+        yield return new object[] { CreateSend(accessCount: 6, maxAccessCount: 5, emails: null, password: null, AuthType.None), typeof(NeverAuthenticate) };
+        yield return new object[] { CreateSend(accessCount: 0, maxAccessCount: 10, emails: "test@example.com", password: null, AuthType.Email), typeof(EmailOtp) };
+        yield return new object[] { CreateSend(accessCount: 0, maxAccessCount: 10, emails: null, password: "hashedpassword", AuthType.Password), typeof(ResourcePassword) };
+        yield return new object[] { CreateSend(accessCount: 0, maxAccessCount: 10, emails: null, password: null, AuthType.None), typeof(NotAuthenticated) };
     }
 
     public static IEnumerable<object[]> EmailParsingTestCases()
@@ -121,7 +122,7 @@ public class SendAuthenticationQueryTests
         yield return new object[] { " , test@example.com,  ,other@example.com, ", new[] { "test@example.com", "other@example.com" } };
     }
 
-    private static Send CreateSend(int accessCount, int? maxAccessCount, string? emails, string? password)
+    private static Send CreateSend(int accessCount, int? maxAccessCount, string? emails, string? password, AuthType? authType)
     {
         return new Send
         {
@@ -129,7 +130,8 @@ public class SendAuthenticationQueryTests
             AccessCount = accessCount,
             MaxAccessCount = maxAccessCount,
             Emails = emails,
-            Password = password
+            Password = password,
+            AuthType = authType
         };
     }
 }

test/Core.Test/Tools/Services/SendOwnerQueryTests.cs

@@ -12,7 +12,6 @@ namespace Bit.Core.Test.Tools.Services;
 public class SendOwnerQueryTests
 {
     private readonly ISendRepository _sendRepository;
-    private readonly IFeatureService _featureService;
     private readonly IUserService _userService;
     private readonly SendOwnerQuery _sendOwnerQuery;
     private readonly Guid _currentUserId = Guid.NewGuid();
@@ -21,11 +20,10 @@ public class SendOwnerQueryTests
     public SendOwnerQueryTests()
     {
         _sendRepository = Substitute.For<ISendRepository>();
-        _featureService = Substitute.For<IFeatureService>();
         _userService = Substitute.For<IUserService>();
         _user = new ClaimsPrincipal();
         _userService.GetProperUserId(_user).Returns(_currentUserId);
-        _sendOwnerQuery = new SendOwnerQuery(_sendRepository, _featureService, _userService);
+        _sendOwnerQuery = new SendOwnerQuery(_sendRepository, _userService);
     }
 
     [Fact]
@@ -84,7 +82,7 @@ public class SendOwnerQueryTests
     }
 
     [Fact]
-    public async Task GetOwned_WithFeatureFlagEnabled_ReturnsAllSends()
+    public async Task GetOwned_ReturnsAllSendsIncludingEmailOTP()
     {
         // Arrange
         var sends = new List<Send>
@@ -94,7 +92,6 @@ public class SendOwnerQueryTests
             CreateSend(Guid.NewGuid(), _currentUserId, emails: "other@example.com")
         };
         _sendRepository.GetManyByUserIdAsync(_currentUserId).Returns(sends);
-        _featureService.IsEnabled(FeatureFlagKeys.PM19051_ListEmailOtpSends).Returns(true);
 
         // Act
         var result = await _sendOwnerQuery.GetOwned(_user);
@@ -105,28 +102,6 @@ public class SendOwnerQueryTests
         Assert.Contains(sends[1], result);
         Assert.Contains(sends[2], result);
         await _sendRepository.Received(1).GetManyByUserIdAsync(_currentUserId);
-        _featureService.Received(1).IsEnabled(FeatureFlagKeys.PM19051_ListEmailOtpSends);
-    }
-
-    [Fact]
-    public async Task GetOwned_WithFeatureFlagDisabled_FiltersOutEmailOtpSends()
-    {
-        // Arrange
-        var sendWithoutEmails = CreateSend(Guid.NewGuid(), _currentUserId, emails: null);
-        var sendWithEmails = CreateSend(Guid.NewGuid(), _currentUserId, emails: "test@example.com");
-        var sends = new List<Send> { sendWithoutEmails, sendWithEmails };
-        _sendRepository.GetManyByUserIdAsync(_currentUserId).Returns(sends);
-        _featureService.IsEnabled(FeatureFlagKeys.PM19051_ListEmailOtpSends).Returns(false);
-
-        // Act
-        var result = await _sendOwnerQuery.GetOwned(_user);
-
-        // Assert
-        Assert.Single(result);
-        Assert.Contains(sendWithoutEmails, result);
-        Assert.DoesNotContain(sendWithEmails, result);
-        await _sendRepository.Received(1).GetManyByUserIdAsync(_currentUserId);
-        _featureService.Received(1).IsEnabled(FeatureFlagKeys.PM19051_ListEmailOtpSends);
     }
 
     [Fact]
@@ -147,7 +122,6 @@ public class SendOwnerQueryTests
         // Arrange
         var emptySends = new List<Send>();
         _sendRepository.GetManyByUserIdAsync(_currentUserId).Returns(emptySends);
-        _featureService.IsEnabled(FeatureFlagKeys.PM19051_ListEmailOtpSends).Returns(true);
 
         // Act
         var result = await _sendOwnerQuery.GetOwned(_user);