diff --git a/Source/Contracts/ContentTransformations/IContentEncryptor.cs b/Source/Contracts/ContentTransformations/IContentEncryptor.cs
index de5e83e..41d1dd0 100644
--- a/Source/Contracts/ContentTransformations/IContentEncryptor.cs
+++ b/Source/Contracts/ContentTransformations/IContentEncryptor.cs
@@ -1,4 +1,4 @@
-namespace EternalArrowBackup.Contracts.Encryption
+namespace EternalArrowBackup.Contracts.ContentTransformations
 {
     using System.Threading.Tasks;
 
@@ -6,6 +6,6 @@
     {
         Task<byte[]> Encrypt(byte[] originalData);
 
-        Task<byte[]> Decrypt(byte[] encryptedData);
+        Task<IDecryptionResult> Decrypt(byte[] encryptedData);
     }
 }
diff --git a/Source/Contracts/ContentTransformations/IContentHasher.cs b/Source/Contracts/ContentTransformations/IContentHasher.cs
index 2dde010..0c255c3 100644
--- a/Source/Contracts/ContentTransformations/IContentHasher.cs
+++ b/Source/Contracts/ContentTransformations/IContentHasher.cs
@@ -1,5 +1,6 @@
 namespace EternalArrowBackup.Contracts.ContentTransformations
 {
+    using System.IO;
     using System.Threading.Tasks;
 
     public interface IContentHasher
diff --git a/Source/Contracts/ContentTransformations/IDecryptionResult.cs b/Source/Contracts/ContentTransformations/IDecryptionResult.cs
new file mode 100644
index 0000000..177397d
--- /dev/null
+++ b/Source/Contracts/ContentTransformations/IDecryptionResult.cs
@@ -0,0 +1,9 @@
+namespace EternalArrowBackup.Contracts.ContentTransformations
+{
+    public interface IDecryptionResult
+    {
+        bool IsSuccessful { get; }
+
+        byte[] Data { get; }
+    }
+}
diff --git a/Source/Contracts/TargetStorage/ITargetDirectory.cs b/Source/Contracts/TargetStorage/ITargetDirectory.cs
index eb66b82..f0ad6ef 100644
--- a/Source/Contracts/TargetStorage/ITargetDirectory.cs
+++ b/Source/Contracts/TargetStorage/ITargetDirectory.cs
@@ -6,24 +6,7 @@
 
     public interface ITargetDirectory
     {
-        /// <summary>
-        /// Uploads new content to the target directory, and adds new entity with DateTime.UtcNow to the list of files
-        /// </summary>
-        /// <param name="filename">File name</param>
-        /// <param name="content">Content</param>
-        /// <param name="hash">File hash</param>
-        /// <returns>Task</returns>
-        Task UploadNewContent(string filename, byte[] content, string hash);
-
-        /// <summary>
-        /// Adds new entity with DateTime.UtcNow to the list of files.
-        /// 
-        /// Example: file "abc.txt" with content "qwe" (v1) was replaced with "rty" (v2), and then was replaced with "qwe" (v3) again.
-        /// The client should <see cref="UploadNewContent(string, byte[], string)"/> for v1 and v2, and then call this method (passing v1 FileInfo to it) for v3.
-        /// </summary>
-        /// <param name="file"></param>
-        /// <returns></returns>
-        Task UpdateExistingContent(ITargetFile file);
+        Task UploadFile(string filename, byte[] data, string originalHash, long originalSize);
 
         IObservable<ITargetFile> GetAllFiles(CancellationToken ct);
     }