diff --git a/src/iTextSharp.LGPLv2.Core/iTextSharp.LGPLv2.Core.csproj b/src/iTextSharp.LGPLv2.Core/iTextSharp.LGPLv2.Core.csproj
index 2b596f2..ecc53ab 100644
--- a/src/iTextSharp.LGPLv2.Core/iTextSharp.LGPLv2.Core.csproj
+++ b/src/iTextSharp.LGPLv2.Core/iTextSharp.LGPLv2.Core.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <Description> iTextSharp.LGPLv2.Core is an unofficial port of the last LGPL version of the iTextSharp (V4.1.6) to .NET Core.</Description>
-    <VersionPrefix>1.3.3</VersionPrefix>
+    <VersionPrefix>1.3.4</VersionPrefix>
     <LangVersion>latest</LangVersion>
     <Authors>Vahid Nasiri</Authors>
     <TargetFrameworks>netstandard1.3;netstandard2.0</TargetFrameworks>
@@ -28,7 +28,7 @@
   </PropertyGroup>
   <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard1.3' ">
     <PackageReference Include="CoreCompat.System.Drawing" Version="1.0.0-beta006" />
-    <PackageReference Include="Portable.BouncyCastle" Version="1.8.1.2" />
+    <PackageReference Include="Portable.BouncyCastle" Version="1.8.1.3" />
     <PackageReference Include="System.Collections.NonGeneric" Version="4.3.0" />
     <PackageReference Include="System.Net.Requests" Version="4.3.0" />
     <PackageReference Include="System.Reflection.TypeExtensions" Version="4.3.0" />
@@ -42,8 +42,8 @@
     <DefineConstants>NETSTANDARD1_3</DefineConstants>
   </PropertyGroup>
   <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' ">
-    <PackageReference Include="CoreCompat.System.Drawing.v2" Version="5.2.0-preview1-r131" />
-    <PackageReference Include="Portable.BouncyCastle" Version="1.8.1.2" />
+    <PackageReference Include="System.Drawing.Common" Version="4.5.0-preview1-25914-04" />
+    <PackageReference Include="Portable.BouncyCastle" Version="1.8.1.3" />
     <PackageReference Include="System.Collections.NonGeneric" Version="4.3.0" />
     <PackageReference Include="System.Net.Requests" Version="4.3.0" />
     <PackageReference Include="System.Reflection.TypeExtensions" Version="4.4.0" />
diff --git a/src/iTextSharp.LGPLv2.Core/iTextSharp/text/pdf/OcspClientBouncyCastle.cs b/src/iTextSharp.LGPLv2.Core/iTextSharp/text/pdf/OcspClientBouncyCastle.cs
index cee0d0e..e612173 100644
--- a/src/iTextSharp.LGPLv2.Core/iTextSharp/text/pdf/OcspClientBouncyCastle.cs
+++ b/src/iTextSharp.LGPLv2.Core/iTextSharp/text/pdf/OcspClientBouncyCastle.cs
@@ -7,6 +7,7 @@
 using Org.BouncyCastle.Asn1;
 using Org.BouncyCastle.Asn1.X509;
 using Org.BouncyCastle.Asn1.Ocsp;
+using System.Collections.Generic;
 
 namespace iTextSharp.text.pdf
 {
@@ -62,7 +63,7 @@ public byte[] GetEncoded()
             outp.Dispose();
             HttpWebResponse response = (HttpWebResponse)con.GetResponseAsync().Result;
             if (response.StatusCode != HttpStatusCode.OK)
-                throw new IOException($"Invalid HTTP response: {(int) response.StatusCode}");
+                throw new IOException($"Invalid HTTP response: {(int)response.StatusCode}");
             Stream inp = response.GetResponseStream();
             OcspResp ocspResponse = new OcspResp(inp);
             inp.Dispose();
@@ -114,8 +115,8 @@ private static OcspReq generateOcspRequest(X509Certificate issuerCert, BigIntege
             gen.AddRequest(id);
 
             // create details for nonce extension
-            ArrayList oids = new ArrayList();
-            ArrayList values = new ArrayList();
+            var oids = new List<object>();
+            var values = new List<object>();
 
             oids.Add(OcspObjectIdentifiers.PkixOcspNonce);
             values.Add(new X509Extension(false, new DerOctetString(new DerOctetString(PdfEncryption.CreateDocumentId()).GetEncoded())));
diff --git a/src/iTextSharp.LGPLv2.Core/iTextSharp/text/pdf/crypto/AESCipher.cs b/src/iTextSharp.LGPLv2.Core/iTextSharp/text/pdf/crypto/AESCipher.cs
index 79701d3..8a8c485 100644
--- a/src/iTextSharp.LGPLv2.Core/iTextSharp/text/pdf/crypto/AESCipher.cs
+++ b/src/iTextSharp.LGPLv2.Core/iTextSharp/text/pdf/crypto/AESCipher.cs
@@ -6,7 +6,7 @@
 
 namespace iTextSharp.text.pdf.crypto
 {
-        /// <summary>
+    /// <summary>
     /// Creates an AES Cipher with CBC and padding PKCS5/7.
     /// @author Paulo Soares (psoares@consiste.pt)
     /// </summary>
@@ -19,7 +19,7 @@ public class AesCipher
         /// </summary>
         public AesCipher(bool forEncryption, byte[] key, byte[] iv)
         {
-            IBlockCipher aes = new AesFastEngine();
+            IBlockCipher aes = new AesEngine();
             IBlockCipher cbc = new CbcBlockCipher(aes);
             _bp = new PaddedBufferedBlockCipher(cbc);
             KeyParameter kp = new KeyParameter(key);