diff --git a/Component_Tests/Classes/Crypto/Omemo/Test_KeyHelper.cs b/Component_Tests/Classes/Crypto/Omemo/Test_KeyHelper.cs
index 3c55217d..da4b842c 100644
--- a/Component_Tests/Classes/Crypto/Omemo/Test_KeyHelper.cs
+++ b/Component_Tests/Classes/Crypto/Omemo/Test_KeyHelper.cs
@@ -2,9 +2,9 @@
 using System.Collections.Generic;
 using System.Text;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
-using NSec.Cryptography;
 using Omemo.Classes;
 using Omemo.Classes.Keys;
+using Org.BouncyCastle.Math.EC.Rfc8032;
 using Shared.Classes;
 
 namespace Component_Tests.Classes.Crypto.Omemo
@@ -56,7 +56,9 @@ public void Test_SignPreKey()
             for (uint id = 1; id < 250; id++)
             {
                 byte[] data = Encoding.ASCII.GetBytes("Message for Ed25519 signing");
-                byte[] signature = SignatureAlgorithm.Ed25519.Sign(Key.Import(SignatureAlgorithm.Ed25519, identityKeyPair.privKey.key, KeyBlobFormat.RawPrivateKey), data);
+
+                byte[] signature = new byte[Ed25519.SignatureSize];
+                Ed25519.Sign(identityKeyPair.privKey.key, 0, data, 0, data.Length, signature, 0);
                 byte[] sigRef = SharedUtils.HexStringToByteArray("6dd355667fae4eb43c6e0ab92e870edb2de0a88cae12dbd8591507f584fe4912babff497f1b8edf9567d2483d54ddc6459bea7855281b7a246a609e3001a4e08");
                 string sigRefBase64 = Convert.ToBase64String(sigRef);
                 string sigBase64 = Convert.ToBase64String(signature);
diff --git a/Omemo/Classes/KeyHelper.cs b/Omemo/Classes/KeyHelper.cs
index dea6988f..bbdcecc1 100644
--- a/Omemo/Classes/KeyHelper.cs
+++ b/Omemo/Classes/KeyHelper.cs
@@ -1,6 +1,6 @@
 using System.Collections.Generic;
-using NSec.Cryptography;
 using Omemo.Classes.Keys;
+using Org.BouncyCastle.Math.EC.Rfc8032;
 using X25519;
 
 namespace Omemo.Classes
@@ -9,8 +9,8 @@ public static class KeyHelper
     {
         //--------------------------------------------------------Attributes:-----------------------------------------------------------------\\
         #region --Attributes--
-        public static int PUB_KEY_SIZE = SignatureAlgorithm.Ed25519.PublicKeySize;
-        public static int PRIV_KEY_SIZE = SignatureAlgorithm.Ed25519.PrivateKeySize;
+        public static int PUB_KEY_SIZE = Ed25519.PublicKeySize;
+        public static int PRIV_KEY_SIZE = Ed25519.SecretKeySize;
 
         #endregion
         //--------------------------------------------------------Constructor:----------------------------------------------------------------\\
@@ -95,8 +95,9 @@ public static SignedPreKeyModel GenerateSignedPreKey(uint id, ECPrivKeyModel ide
         public static byte[] SignPreKey(PreKeyModel preKey, ECPrivKeyModel identiyKey)
         {
             byte[] pubKey = preKey.pubKey.ToByteArrayWithPrefix();
-            Key key = Key.Import(SignatureAlgorithm.Ed25519, identiyKey.key, KeyBlobFormat.RawPrivateKey);
-            return SignatureAlgorithm.Ed25519.Sign(key, pubKey);
+            byte[] signature = new byte[Ed25519.SignatureSize];
+            Ed25519.Sign(identiyKey.key, 0, pubKey, 0, pubKey.Length, signature, 0);
+            return signature;
         }
 
         /// <summary>
@@ -108,7 +109,7 @@ public static byte[] SignPreKey(PreKeyModel preKey, ECPrivKeyModel identiyKey)
         /// <returns>True in case the signature is valid.</returns>
         public static bool VerifySignature(ECPubKeyModel identityKey, ECPubKeyModel preKey, byte[] signature)
         {
-            return SignatureAlgorithm.Ed25519.Verify(PublicKey.Import(SignatureAlgorithm.Ed25519, identityKey.key, KeyBlobFormat.RawPublicKey), preKey.ToByteArrayWithPrefix(), signature);
+            return Ed25519.Verify(signature, 0, identityKey.key, 0, preKey.key, 0, preKey.key.Length);
         }
 
         /// <summary>
diff --git a/Omemo/Omemo.csproj b/Omemo/Omemo.csproj
index 88689cb5..55b09111 100644
--- a/Omemo/Omemo.csproj
+++ b/Omemo/Omemo.csproj
@@ -160,9 +160,6 @@
     <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform">
       <Version>6.2.13</Version>
     </PackageReference>
-    <PackageReference Include="NSec.Cryptography">
-      <Version>20.2.0</Version>
-    </PackageReference>
     <PackageReference Include="Portable.BouncyCastle">
       <Version>1.9.0</Version>
     </PackageReference>
@@ -177,11 +174,6 @@
       <Name>Shared</Name>
     </ProjectReference>
   </ItemGroup>
-  <ItemGroup>
-    <SDKReference Include="Microsoft.VCLibs.Desktop, Version=14.0">
-      <Name>Visual C++ 2015-2019 UWP Desktop Runtime for native apps</Name>
-    </SDKReference>
-  </ItemGroup>
   <PropertyGroup Condition=" '$(VisualStudioVersion)' == '' or '$(VisualStudioVersion)' &lt; '14.0' ">
     <VisualStudioVersion>14.0</VisualStudioVersion>
   </PropertyGroup>