diff --git a/Include/Common/OPC/NMR_IOpcPackageWriter.h b/Include/Common/OPC/NMR_IOpcPackageWriter.h
index 78a825033..838707a8e 100644
--- a/Include/Common/OPC/NMR_IOpcPackageWriter.h
+++ b/Include/Common/OPC/NMR_IOpcPackageWriter.h
@@ -3,6 +3,7 @@
 
 #include <memory>
 #include <string>
+#include <list>
 #include "Common/NMR_Types.h"
 #include "Common/NMR_Local.h"
 
@@ -19,6 +20,7 @@ namespace NMR {
 		virtual void addContentType(_In_ POpcPackagePart pOpcPackagePart, _In_ std::string sContentType) = 0;
 		virtual POpcPackageRelationship addRootRelationship(_In_ std::string sType, _In_ COpcPackagePart * pTargetPart) = 0;
 		virtual POpcPackageRelationship addPartRelationship(_In_ POpcPackagePart pOpcPackagePart, _In_ std::string sType, _In_ COpcPackagePart * pTargetPart) = 0;
+		virtual std::list<POpcPackageRelationship> addWriterSpecificRelationships(_In_ POpcPackagePart pOpcPackagePart, _In_ COpcPackagePart* pTargetPart) = 0;
 		virtual void close() {}
 	};
 
diff --git a/Include/Common/OPC/NMR_OpcPackageWriter.h b/Include/Common/OPC/NMR_OpcPackageWriter.h
index b134f893c..5bbf3bfc5 100644
--- a/Include/Common/OPC/NMR_OpcPackageWriter.h
+++ b/Include/Common/OPC/NMR_OpcPackageWriter.h
@@ -72,6 +72,7 @@ namespace NMR {
 		void addContentType(_In_ POpcPackagePart pOpcPackagePart, _In_ std::string sContentType) override;
 		POpcPackageRelationship addRootRelationship(_In_ std::string sType, _In_ COpcPackagePart * pTargetPart) override;
 		POpcPackageRelationship addPartRelationship(_In_ POpcPackagePart pOpcPackagePart, _In_ std::string sType, _In_ COpcPackagePart * pTargetPart) override;
+		std::list<POpcPackageRelationship> addWriterSpecificRelationships(_In_ POpcPackagePart pOpcPackagePart, _In_ COpcPackagePart* pTargetPart) override;
 	};
 
 	typedef std::shared_ptr<COpcPackageWriter> POpcPackageWriter;
diff --git a/Include/Model/Classes/NMR_ModelConstants.h b/Include/Model/Classes/NMR_ModelConstants.h
index 129e7e9de..21191891b 100644
--- a/Include/Model/Classes/NMR_ModelConstants.h
+++ b/Include/Model/Classes/NMR_ModelConstants.h
@@ -71,6 +71,7 @@ These are given by the 3MF Standard
 #define PACKAGE_THUMBNAIL_RELATIONSHIP_TYPE "http://schemas.openxmlformats.org/package/2006/relationships/metadata/thumbnail"
 #define PACKAGE_MUST_PRESERVE_RELATIONSHIP_TYPE "http://schemas.openxmlformats.org/package/2006/relationships/mustpreserve"
 #define PACKAGE_KEYSTORE_RELATIONSHIP_TYPE "http://schemas.microsoft.com/3dmanufacturing/2019/04/keystore"
+#define PACKAGE_ENCRYPTED_FILE_RELATIONSHIP "http://schemas.openxmlformats.org/package/2006/relationships/encryptedfile"
 
 #define XML_3MF_NAMESPACE_XML "http://www.w3.org/XML/1998/namespace"
 #define XML_3MF_NAMESPACE_XMLNS "http://www.w3.org/2000/xmlns/"
diff --git a/Include/Model/Writer/NMR_KeyStoreOpcPackageWriter.h b/Include/Model/Writer/NMR_KeyStoreOpcPackageWriter.h
index c42f9c52f..83a50e9b6 100644
--- a/Include/Model/Writer/NMR_KeyStoreOpcPackageWriter.h
+++ b/Include/Model/Writer/NMR_KeyStoreOpcPackageWriter.h
@@ -49,6 +49,8 @@ namespace NMR {
 	using PKeyStoreAccessRight = std::shared_ptr<CKeyStoreAccessRight>;
 
 	class CKeyStoreOpcPackageWriter : public IOpcPackageWriter {
+	private:
+		bool pathIsEncrypted(_In_ std::string sPath);
 	protected:
 		CModelContext const & m_pContext;
 		PIOpcPackageWriter m_pPackageWriter;
@@ -69,6 +71,7 @@ namespace NMR {
 		void addContentType(_In_ POpcPackagePart pOpcPackagePart, _In_ std::string sContentType) override;
 		POpcPackageRelationship addRootRelationship(std::string sType, COpcPackagePart * pTargetPart) override;
 		POpcPackageRelationship addPartRelationship(_In_ POpcPackagePart pOpcPackagePart, _In_ std::string sType, _In_ COpcPackagePart * pTargetPart) override;
+		std::list<POpcPackageRelationship> addWriterSpecificRelationships(_In_ POpcPackagePart pOpcPackagePart, _In_ COpcPackagePart* pTargetPart) override;
 	};
 
 	using PKeyStoreOpcPackageWriter = std::shared_ptr<CKeyStoreOpcPackageWriter>;
diff --git a/Source/Common/OPC/NMR_OpcPackageWriter.cpp b/Source/Common/OPC/NMR_OpcPackageWriter.cpp
index 60b983f4d..c0112f9da 100644
--- a/Source/Common/OPC/NMR_OpcPackageWriter.cpp
+++ b/Source/Common/OPC/NMR_OpcPackageWriter.cpp
@@ -121,6 +121,11 @@ namespace NMR {
 		return pOpcPackagePart->addRelationship(generateRelationShipID(), sType, pTargetPart->getURI());
 	}
 
+	std::list<POpcPackageRelationship> COpcPackageWriter::addWriterSpecificRelationships(_In_ POpcPackagePart pOpcPackagePart, _In_ COpcPackagePart* pTargetPart)
+	{
+		return std::list<POpcPackageRelationship>();
+	}
+
 	void COpcPackageWriter::finishPackage()
 	{
 		writeContentTypes();
diff --git a/Source/Model/Writer/NMR_KeyStoreOpcPackageWriter.cpp b/Source/Model/Writer/NMR_KeyStoreOpcPackageWriter.cpp
index d568b8b12..a61a9d7bd 100644
--- a/Source/Model/Writer/NMR_KeyStoreOpcPackageWriter.cpp
+++ b/Source/Model/Writer/NMR_KeyStoreOpcPackageWriter.cpp
@@ -91,6 +91,23 @@ namespace NMR {
 		}
 	}
 
+	bool CKeyStoreOpcPackageWriter::pathIsEncrypted(_In_ std::string sPath)
+	{
+		PSecureContext const& secureContext = m_pContext.secureContext();
+		PKeyStore const& keyStore = m_pContext.keyStore();
+
+		NMR::PKeyStoreResourceData rd = keyStore->findResourceData(sPath);
+		if (nullptr != rd) {
+			if (secureContext->hasDekCtx()) {
+				return true;
+			}
+			else {
+				m_pContext.warnings()->addWarning(NMR_ERROR_DEKDESCRIPTORNOTFOUND, eModelWarningLevel::mrwMissingMandatoryValue);
+			}
+		}
+		return false;
+	}
+
 	POpcPackagePart CKeyStoreOpcPackageWriter::wrapPartStream(PKeyStoreResourceData rd, POpcPackagePart part) {
 		PSecureContext const & secureContext = m_pContext.secureContext();
 		ContentEncryptionDescriptor p = secureContext->getDekCtx();
@@ -190,6 +207,19 @@ namespace NMR {
 		return m_pPackageWriter->addPartRelationship(pOpcPackagePart, sType, pTargetPart);
 	}
 
+	std::list<POpcPackageRelationship> CKeyStoreOpcPackageWriter::addWriterSpecificRelationships(_In_ POpcPackagePart pOpcPackagePart, _In_ COpcPackagePart* pTargetPart)
+	{
+		std::list<POpcPackageRelationship> list;
+		std::string sPath = fnIncludeLeadingPathDelimiter(pTargetPart->getURI());
+		if (pathIsEncrypted(sPath))
+		{
+			list.push_back(addPartRelationship(pOpcPackagePart, PACKAGE_ENCRYPTED_FILE_RELATIONSHIP, pTargetPart));
+		}
+
+		list.merge(m_pPackageWriter->addWriterSpecificRelationships(pOpcPackagePart, pTargetPart));
+		return list;
+	}
+
 	void CKeyStoreOpcPackageWriter::writeKeyStoreStream(_In_ CXmlWriter * pXMLWriter) {
 		pXMLWriter->WriteStartDocument();
 
diff --git a/Source/Model/Writer/NMR_ModelWriter_3MF_Native.cpp b/Source/Model/Writer/NMR_ModelWriter_3MF_Native.cpp
index ceb2a6f3e..7aea896d3 100644
--- a/Source/Model/Writer/NMR_ModelWriter_3MF_Native.cpp
+++ b/Source/Model/Writer/NMR_ModelWriter_3MF_Native.cpp
@@ -200,7 +200,7 @@ namespace NMR {
 				if (pStream.get() == nullptr)
 					throw CNMRException(NMR_ERROR_INVALIDPARAM);
 
-				// create Texture Part
+				// create Attachment Part
 				POpcPackagePart pAttachmentPart = m_pPackageWriter->addPart(sPath);
 				PExportStream pExportStream = pAttachmentPart->getExportStream();
 
@@ -211,6 +211,8 @@ namespace NMR {
 				// add relationships
 				m_pPackageWriter->addPartRelationship(pModelPart, sRelationShipType.c_str(), pAttachmentPart.get());
 
+				m_pPackageWriter->addWriterSpecificRelationships(pModelPart, pAttachmentPart.get());
+
 				monitor()->IncrementProgress(1);
 			}
 		}