diff --git a/messagecomposer/src/composer/composer.cpp b/messagecomposer/src/composer/composer.cpp
--- a/messagecomposer/src/composer/composer.cpp
+++ b/messagecomposer/src/composer/composer.cpp
@@ -274,6 +274,7 @@
             seJob->setSigningKeys(signers);
             seJob->setEncryptionKeys(recipients.second);
             seJob->setRecipients(recipients.first);
+            seJob->setSkeletonMessage(skeletonMessage);
 
             subJob = seJob;
         } else {
diff --git a/messagecomposer/src/job/signencryptjob.h b/messagecomposer/src/job/signencryptjob.h
--- a/messagecomposer/src/job/signencryptjob.h
+++ b/messagecomposer/src/job/signencryptjob.h
@@ -57,12 +57,18 @@
     void setEncryptionKeys(const std::vector<GpgME::Key> &keys) override;
     void setRecipients(const QStringList &rec) override;
 
+    void setSkeletonMessage(KMime::Message *skeletonMessage);
+
+    void setProtectedHeaders(bool protectedHeaders);
+    void setProtectedHeadersObvoscate(bool protectedHeadersObvoscate);
+
     Q_REQUIRED_RESULT std::vector<GpgME::Key> encryptionKeys() const override;
     Q_REQUIRED_RESULT QStringList recipients() const override;
 
     Q_REQUIRED_RESULT KMime::Content *origContent();
 
 protected Q_SLOTS:
+    void doStart() override;
     void process() override;
 
 private:
diff --git a/messagecomposer/src/job/signencryptjob.cpp b/messagecomposer/src/job/signencryptjob.cpp
--- a/messagecomposer/src/job/signencryptjob.cpp
+++ b/messagecomposer/src/job/signencryptjob.cpp
@@ -21,7 +21,7 @@
 #include "job/signencryptjob.h"
 
 #include "contentjobbase_p.h"
-#include "utils/util.h"
+#include "job/protectedheaders.h"
 #include "utils/util_p.h"
 
 #include <Libkleo/Enum>
@@ -54,6 +54,10 @@
     QStringList recipients;
     Kleo::CryptoMessageFormat format;
     KMime::Content *content = nullptr;
+    KMime::Message *skeletonMessage = nullptr;
+
+    bool protectedHeaders = true;
+    bool protectedHeadersObvoscate = false;
 
     // copied from messagecomposer.cpp
     bool binaryHint(Kleo::CryptoMessageFormat f)
@@ -130,6 +134,27 @@
     d->recipients = recipients;
 }
 
+void SignEncryptJob::setSkeletonMessage(KMime::Message *skeletonMessage)
+{
+    Q_D(SignEncryptJob);
+
+    d->skeletonMessage = skeletonMessage;
+}
+
+void SignEncryptJob::setProtectedHeaders(bool protectedHeaders)
+{
+    Q_D(SignEncryptJob);
+
+    d->protectedHeaders = protectedHeaders;
+}
+
+void SignEncryptJob::setProtectedHeadersObvoscate(bool protectedHeadersObvoscate)
+{
+    Q_D(SignEncryptJob);
+
+    d->protectedHeadersObvoscate = protectedHeadersObvoscate;
+}
+
 QStringList SignEncryptJob::recipients() const
 {
     Q_D(const SignEncryptJob);
@@ -144,6 +169,28 @@
     return d->encKeys;
 }
 
+void SignEncryptJob::doStart()
+{
+    Q_D(SignEncryptJob);
+    Q_ASSERT(d->resultContent == nullptr);   // Not processed before.
+
+    if (d->protectedHeaders && d->skeletonMessage && d->format & Kleo::OpenPGPMIMEFormat) {
+        ProtectedHeadersJob *pJob = new ProtectedHeadersJob;
+        pJob->setContent(d->content);
+        pJob->setSkeletonMessage(d->skeletonMessage);
+        pJob->setObvoscate(d->protectedHeadersObvoscate);
+        QObject::connect(pJob, &ProtectedHeadersJob::finished, this, [d, pJob](KJob *job) {
+            if (job->error()) {
+                return;
+            }
+            d->content = pJob->content();
+        });
+        appendSubjob(pJob);
+    }
+
+    ContentJobBase::doStart();
+}
+
 void SignEncryptJob::process()
 {
     Q_D(SignEncryptJob);