diff --git a/KeyEdit.cpp b/KeyEdit.cpp
index e14f674..0f6f633 100644
--- a/KeyEdit.cpp
+++ b/KeyEdit.cpp
@@ -145,10 +145,9 @@ void KeyEdit::OnUidValidityClicked(WTreeTableNode* uidNode, vector<WString>& pri
 
 void KeyEdit::EditUidValidity()
 {
-    vector<uint>& uidsToSign = m_popupCertifyUid->GetUidsToSign();
-    if (uidsToSign.size() == 0)
+    if (!m_popupCertifyUid->Validate())
     {
-        m_owner->m_tmwMessage->SetText(TR("NoUidSelected"));
+        m_owner->m_tmwMessage->SetText(TR("InvalidInput"));
         return;
     }
     const WString signingKey = m_popupCertifyUid->GetSelectedKey();
@@ -157,6 +156,7 @@ void KeyEdit::EditUidValidity()
     GpgME::Error e;
     if (m_popupCertifyUid->WhatToDo() == PopupCertifyUserId::CertifyUid)
     {
+        vector<uint>& uidsToSign = m_popupCertifyUid->GetUidsToSign();
         int options = m_popupCertifyUid->GetCertifyOptions();
         e = gpgWorker.CertifyKey(signingKey.toUTF8().c_str(),
                                  keyToSign.toUTF8().c_str(),
diff --git a/PopupCertifyUserId.cpp b/PopupCertifyUserId.cpp
index b6d0b12..bef647a 100644
--- a/PopupCertifyUserId.cpp
+++ b/PopupCertifyUserId.cpp
@@ -28,6 +28,7 @@ PopupCertifyUserId::PopupCertifyUserId(WWidget * anchorWidget, TransientMessageW
     m_cbOptionExportable = NULL;
     m_cbOptionNonRevocable = NULL;
     // m_cbOptionTrust = NULL;
+    m_cbConfirm = NULL;
     m_lblPassphrase = NULL;
     m_lePassphrase = NULL;
     m_btnApply = NULL;
@@ -98,6 +99,9 @@ void PopupCertifyUserId::Create(vector<WString>& privateKeys,
     m_bgWhat->setCheckedButton(rbCertifyUid);
     vblMain->addLayout(unique_ptr<WHBoxLayout> (hblWhat));
 
+    m_cbConfirm = new WCheckBox(TR("Confirm"));
+    vblMain->addWidget(unique_ptr<WCheckBox> (m_cbConfirm));
+
     WHBoxLayout * hblButtons = new WHBoxLayout();
     WPushButton * btnClose = new WPushButton(TR("Close"));
     hblButtons->addWidget(unique_ptr<WPushButton> (btnClose));
@@ -279,3 +283,20 @@ void PopupCertifyUserId::OnButtonGroupWhat(WRadioButton* btn)
                              == What::RevokeUidCertification);
 
 }
+
+bool PopupCertifyUserId::Validate() const
+{
+    if (!m_cbConfirm->isChecked() || m_lePassphrase->text().empty())
+        return false;
+    if (m_bgWhat->checkedId() == What::CertifyUid)
+    {
+        if (m_uidsToSign.size() == 0)
+            return false;
+    }
+    else
+    {
+        if (m_uidsToRevokeCertification.size() == 0)
+            return false;
+    }
+    return true;
+}
diff --git a/PopupCertifyUserId.h b/PopupCertifyUserId.h
index 98a5773..95b4b48 100644
--- a/PopupCertifyUserId.h
+++ b/PopupCertifyUserId.h
@@ -149,6 +149,11 @@ public:
     {
         return m_btnApply;
     }
+    /**
+     * Check required parameters are set and confirmed.
+     * @return 
+     */
+    bool Validate() const;
 private:
     TransientMessageWidget * m_tmwMessage;
     WContainerWidget * m_cwMain;
@@ -163,6 +168,7 @@ private:
     // WCheckBox * m_cbOptionTrust; // Always fails
     WText * m_lblPassphrase;
     WLineEdit * m_lePassphrase;
+    WCheckBox * m_cbConfirm;
     WPushButton * m_btnApply;
 
     vector<uint> m_uidsToSign;