Read-mode working

Write-mode does not create exceptions but still doesn't work

ModernKeePassLib/Cryptography/CryptographicHashExtensions.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.InteropServices.WindowsRuntime;
+using System.Text;
+using System.Threading.Tasks;
+using Windows.Security.Cryptography.Core;
+
+namespace ModernKeePassLibPCL.Cryptography
+{
+    public static class CryptographicHashExtensions
+    {
+        public static int TransformBlock(this CryptographicHash hash, byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
+        {
+            byte[] buffer;
+            if (inputCount < inputBuffer.Length)
+            {
+                buffer = new byte[inputCount];
+                Array.Copy(inputBuffer, inputOffset, buffer, 0, inputCount);
+            }
+            else
+            {
+                buffer = inputBuffer;
+            }
+
+            hash.Append(buffer.AsBuffer());
+            if (outputBuffer != null)
+            {
+                Array.Copy(inputBuffer, inputOffset, outputBuffer, outputOffset, inputCount);
+            }
+
+            return inputCount;
+        }
+        
+        public static byte[] TransformFinalBlock(this CryptographicHash hash, byte[] inputBuffer, int inputOffset, int inputCount)
+        {
+            hash.TransformBlock(inputBuffer, inputOffset, inputCount, null, 0);
+            if (inputCount == inputBuffer.Length)
+            {
+                return inputBuffer;
+            }
+            else
+            {
+                var buffer = new byte[inputCount];
+                Array.Copy(inputBuffer, inputOffset, buffer, 0, inputCount);
+                return buffer;
+            }
+        }
+    }
+}