diff --git a/appveyor.yml b/appveyor.yml
index e5528b35e1e9..993061056a5c 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -138,8 +138,8 @@ for:
   - sh: sudo apt-get update
   - sh: sudo apt install -y lsb lsb-core alien libkrb5-dev
   - sh: cd ./cspTools
-  - sh: tar -xf linux_amd64_deb.tar
-  - sh: sudo ./linux_amd64_deb/install.sh
+  - sh: tar -xf linux-amd64_deb.tar
+  - sh: sudo ./linux-amd64_deb/install.sh
   - sh: sudo /opt/cprocsp/sbin/amd64/cpconfig -license -set "5050C-90030-05B5W-LTHVH-PFPU2"
   #install container
   - sh: mkdir -p /var/opt/cprocsp/keys/appveyor/
diff --git a/cspTools/linux-amd64_deb.tar b/cspTools/linux-amd64_deb.tar
new file mode 100644
index 000000000000..6d7e7c302d73
Binary files /dev/null and b/cspTools/linux-amd64_deb.tar differ
diff --git a/cspTools/linux_amd64_deb.tar b/cspTools/linux_amd64_deb.tar
deleted file mode 100644
index 6d263c90f57c..000000000000
Binary files a/cspTools/linux_amd64_deb.tar and /dev/null differ
diff --git a/src/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.Unix.cs b/src/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.Unix.cs
new file mode 100644
index 000000000000..ab7a9c0c20a1
--- /dev/null
+++ b/src/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.Unix.cs
@@ -0,0 +1,61 @@
+using System;
+using System.Security.Cryptography;
+using System.Security.Cryptography.Pkcs;
+using System.Security.Cryptography.Xml;
+using static Interop.Crypt32;
+
+namespace Internal.Cryptography.Pal.Windows
+{
+    internal static partial class HelpersWindows
+    {
+        const int sizeof_wchar_t = 4;
+
+        public static SubjectIdentifier ToSubjectIdentifier(this CERT_ID certId)
+        {
+            switch (certId.dwIdChoice)
+            {
+                case CertIdChoice.CERT_ID_ISSUER_SERIAL_NUMBER:
+                {
+                    const int dwStrType = (int)(CertNameStrTypeAndFlags.CERT_X500_NAME_STR | CertNameStrTypeAndFlags.CERT_NAME_STR_REVERSE_FLAG);
+
+                    string issuer;
+                    unsafe
+                    {
+                        DATA_BLOB* dataBlobPtr = &certId.u.IssuerSerialNumber.Issuer;
+
+                        int nc = Interop.Crypt32.CertNameToStr((int)MsgEncodingType.All, dataBlobPtr, dwStrType, null, 0);
+                        if (nc <= 1) // The API actually return 1 when it fails; which is not what the documentation says.
+                        {
+                            throw Interop.CPError.GetLastWin32Error().ToCryptographicException();
+                        }
+
+                        Span<byte> name = nc <= 256 ? stackalloc byte[nc*sizeof_wchar_t] : new byte[nc*sizeof_wchar_t];
+                        fixed (byte* namePtr = name)
+                        {
+                            nc = Interop.Crypt32.CertNameToStr((int)MsgEncodingType.All, dataBlobPtr, dwStrType, (char*)namePtr, nc);
+                            if (nc <= 1) // The API actually return 1 when it fails; which is not what the documentation says.
+                            {
+                                throw Interop.CPError.GetLastWin32Error().ToCryptographicException();
+                            }
+
+                            issuer = System.Text.Encoding.UTF32.GetString(name.Slice(0, (nc-1)*sizeof_wchar_t).ToArray());
+                        }
+                    }
+
+                    byte[] serial = certId.u.IssuerSerialNumber.SerialNumber.ToByteArray();
+                    X509IssuerSerial issuerSerial = new X509IssuerSerial(issuer, serial.ToSerialString());
+                    return new SubjectIdentifier(SubjectIdentifierType.IssuerAndSerialNumber, issuerSerial);
+                }
+
+                case CertIdChoice.CERT_ID_KEY_IDENTIFIER:
+                {
+                    byte[] ski = certId.u.KeyId.ToByteArray();
+                    return new SubjectIdentifier(SubjectIdentifierType.SubjectKeyIdentifier, ski.ToSkiString());
+                }
+
+                default:
+                    throw new CryptographicException(SR.Format(SR.Cryptography_Cms_Invalid_Subject_Identifier_Type, certId.dwIdChoice));
+            }
+        }
+    }
+}
diff --git a/src/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.Windows.cs b/src/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.Windows.cs
new file mode 100644
index 000000000000..809d08f2460d
--- /dev/null
+++ b/src/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.Windows.cs
@@ -0,0 +1,59 @@
+using System;
+using System.Security.Cryptography;
+using System.Security.Cryptography.Pkcs;
+using System.Security.Cryptography.Xml;
+using static Interop.Crypt32;
+
+namespace Internal.Cryptography.Pal.Windows
+{
+    internal static partial class HelpersWindows
+    {
+        public static SubjectIdentifier ToSubjectIdentifier(this CERT_ID certId)
+        {
+            switch (certId.dwIdChoice)
+            {
+                case CertIdChoice.CERT_ID_ISSUER_SERIAL_NUMBER:
+                {
+                    const int dwStrType = (int)(CertNameStrTypeAndFlags.CERT_X500_NAME_STR | CertNameStrTypeAndFlags.CERT_NAME_STR_REVERSE_FLAG);
+
+                    string issuer;
+                    unsafe
+                    {
+                        DATA_BLOB* dataBlobPtr = &certId.u.IssuerSerialNumber.Issuer;
+
+                        int nc = Interop.Crypt32.CertNameToStr((int)MsgEncodingType.All, dataBlobPtr, dwStrType, null, 0);
+                        if (nc <= 1) // The API actually return 1 when it fails; which is not what the documentation says.
+                        {
+                            throw Interop.CPError.GetLastWin32Error().ToCryptographicException();
+                        }
+
+                        Span<char> name = nc <= 128 ? stackalloc char[128] : new char[nc];
+                        fixed (char* namePtr = name)
+                        {
+                            nc = Interop.Crypt32.CertNameToStr((int)MsgEncodingType.All, dataBlobPtr, dwStrType, namePtr, nc);
+                            if (nc <= 1) // The API actually return 1 when it fails; which is not what the documentation says.
+                            {
+                                throw Interop.CPError.GetLastWin32Error().ToCryptographicException();
+                            }
+
+                            issuer = new string(namePtr);
+                        }
+                    }
+
+                    byte[] serial = certId.u.IssuerSerialNumber.SerialNumber.ToByteArray();
+                    X509IssuerSerial issuerSerial = new X509IssuerSerial(issuer, serial.ToSerialString());
+                    return new SubjectIdentifier(SubjectIdentifierType.IssuerAndSerialNumber, issuerSerial);
+                }
+
+                case CertIdChoice.CERT_ID_KEY_IDENTIFIER:
+                {
+                    byte[] ski = certId.u.KeyId.ToByteArray();
+                    return new SubjectIdentifier(SubjectIdentifierType.SubjectKeyIdentifier, ski.ToSkiString());
+                }
+
+                default:
+                    throw new CryptographicException(SR.Format(SR.Cryptography_Cms_Invalid_Subject_Identifier_Type, certId.dwIdChoice));
+            }
+        }
+    }
+}
diff --git a/src/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.cs b/src/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.cs
index cb88443ce829..fa708c18b470 100644
--- a/src/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.cs
+++ b/src/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.cs
@@ -20,7 +20,7 @@
 
 namespace Internal.Cryptography.Pal.Windows
 {
-    internal static class HelpersWindows
+    internal static partial class HelpersWindows
     {
         public static CryptographicException ToCryptographicException(this ErrorCode errorCode)
         {
@@ -160,55 +160,7 @@ public static unsafe byte[] GetSubjectKeyIdentifer(this SafeCertContextHandle hC
                 throw Interop.CPError.GetLastWin32Error().ToCryptographicException();
 
             return ski.Resize(cbData);
-        }
-
-        public static SubjectIdentifier ToSubjectIdentifier(this CERT_ID certId)
-        {
-            switch (certId.dwIdChoice)
-            {
-                case CertIdChoice.CERT_ID_ISSUER_SERIAL_NUMBER:
-                    {
-                        const int dwStrType = (int)(CertNameStrTypeAndFlags.CERT_X500_NAME_STR | CertNameStrTypeAndFlags.CERT_NAME_STR_REVERSE_FLAG);
-
-                        string issuer;
-                        unsafe
-                        {
-                            DATA_BLOB* dataBlobPtr = &certId.u.IssuerSerialNumber.Issuer;
-
-                            int nc = Interop.Crypt32.CertNameToStr((int)MsgEncodingType.All, dataBlobPtr, dwStrType, null, 0);
-                            if (nc <= 1) // The API actually return 1 when it fails; which is not what the documentation says.
-                            {
-                                throw Interop.CPError.GetLastWin32Error().ToCryptographicException();
-                            }
-
-                            Span<char> name = nc <= 128 ? stackalloc char[128] : new char[nc];
-                            fixed (char* namePtr = name)
-                            {
-                                nc = Interop.Crypt32.CertNameToStr((int)MsgEncodingType.All, dataBlobPtr, dwStrType, namePtr, nc);
-                                if (nc <= 1) // The API actually return 1 when it fails; which is not what the documentation says.
-                                {
-                                    throw Interop.CPError.GetLastWin32Error().ToCryptographicException();
-                                }
-
-                                issuer = new string(namePtr);
-                            }
-                        }
-
-                        byte[] serial = certId.u.IssuerSerialNumber.SerialNumber.ToByteArray();
-                        X509IssuerSerial issuerSerial = new X509IssuerSerial(issuer, serial.ToSerialString());
-                        return new SubjectIdentifier(SubjectIdentifierType.IssuerAndSerialNumber, issuerSerial);
-                    }
-
-                case CertIdChoice.CERT_ID_KEY_IDENTIFIER:
-                    {
-                        byte[] ski = certId.u.KeyId.ToByteArray();
-                        return new SubjectIdentifier(SubjectIdentifierType.SubjectKeyIdentifier, ski.ToSkiString());
-                    }
-
-                default:
-                    throw new CryptographicException(SR.Format(SR.Cryptography_Cms_Invalid_Subject_Identifier_Type, certId.dwIdChoice));
-            }
-        }
+        }        
 
         public static SubjectIdentifierOrKey ToSubjectIdentifierOrKey(this CERT_ID certId)
         {
diff --git a/src/System.Security.Cryptography.Pkcs/src/System.Security.Cryptography.Pkcs.csproj b/src/System.Security.Cryptography.Pkcs/src/System.Security.Cryptography.Pkcs.csproj
index e17431160cab..d08365f1b277 100644
--- a/src/System.Security.Cryptography.Pkcs/src/System.Security.Cryptography.Pkcs.csproj
+++ b/src/System.Security.Cryptography.Pkcs/src/System.Security.Cryptography.Pkcs.csproj
@@ -354,6 +354,7 @@
     <Compile Include="$(CommonPath)\Interop\Windows\Interop.Libraries.cs">
       <Link>Common\Interop\Windows\Interop.Libraries.cs</Link>
     </Compile>
+	<Compile Include="Internal\Cryptography\Pal\Windows\HelpersWindows.Windows.cs" />
     <Compile Include="$(CommonPath)\Interop\Interop.CPGetLastWin32Error.cs">
       <Link>Common\Interop\Interop.CPGetLastWin32Error.cs</Link>
     </Compile>
@@ -386,7 +387,8 @@
     <Compile Include="$(CommonPath)\Interop\Interop.CPGetLastWin32Error.Unix.cs">
       <Link>Common\Interop\Interop.CPGetLastWin32Error.Unix.cs</Link>
     </Compile>
-    <Compile Include="Interop\Unix\NCryptGetByteProperty.Unix.cs"/>
+	<Compile Include="Internal\Cryptography\Pal\Windows\HelpersWindows.Unix.cs" />
+    <Compile Include="Interop\Unix\NCryptGetByteProperty.Unix.cs" />
     <Compile Include="Microsoft\Win32\SafeHandles\SafeProvOrNCryptKeyHandleUwp.Unix.cs" />
     <Compile Include="Interop\Unix\Interop.Heap.Unix.cs" />
     <!-- <Compile Include="Internal\Cryptography\Pal\AnyOS\PkcsPal.AnyOS.cs" /> -->