diff --git a/src/pinentry.hxx b/src/pinentry.hxx
index b61eec0..661c18d 100644
--- a/src/pinentry.hxx
+++ b/src/pinentry.hxx
@@ -8,6 +8,7 @@
 #ifndef __PINDIALOG_HXX__
 #define __PINDIALOG_HXX__
 
+#include <cryptoki.hxx>
 #include <qbrowserlib/log.hxx>
 #include <ui_pinentry.h>
 #include <QtGui/QDialog>
@@ -19,7 +20,9 @@
 class PinEntry: public QDialog, public Ui::PinEntry {
     Q_OBJECT;
   public:
-    PinEntry(const QSslCertificate& cert, QWidget *parent=0): QDialog(parent) {
+    PinEntry(const QSslCertificate& cert, QWidget *parent=0):
+        QDialog(parent),
+        _maxPinLen(-1), _minPinLen(0) {
       setModal(true);
       setupUi(this);
       _cert->certificate(cert);
@@ -37,6 +40,12 @@ class PinEntry: public QDialog, public Ui::PinEntry {
         _certSerial->setText(cert.serialNumber());
       }
     }
+    PinEntry& tokeninfo(const cryptoki::TokenInfo& ti) {
+      _maxPinLen = ti.maxPinLen;
+      _minPinLen = ti.minPinLen;
+      on__pin_textChanged(_pin->text());
+      return *this;
+    }
     PinEntry& retries(int num) {
       _pinstatus->setCurrentIndex(num==-1?1:(num==-2?2:0));
       _retries->setText(tr("there are %1 PIN attempts left").arg(num));
@@ -76,6 +85,11 @@ class PinEntry: public QDialog, public Ui::PinEntry {
       _cert->setVisible(s);
       adjustSize();
     }
+    void on__pin_textChanged(const QString &text) {
+      _buttonBox->button(QDialogButtonBox::Ok)
+        ->setEnabled((unsigned long)text.size()>=_minPinLen &&
+                     (unsigned long)text.size()<=_maxPinLen);
+    }
   protected:
     QString utfConv(const QString& txt) {
       QByteArray value(txt.toAscii());
@@ -85,6 +99,8 @@ class PinEntry: public QDialog, public Ui::PinEntry {
     }
   private:
     QEventLoop _run;
+    unsigned long _maxPinLen;
+    unsigned long _minPinLen;
 };
 
 #endif
diff --git a/src/pinentry.ui b/src/pinentry.ui
index df4df21..f3d95b1 100644
--- a/src/pinentry.ui
+++ b/src/pinentry.ui
@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>668</width>
-    <height>602</height>
+    <width>688</width>
+    <height>594</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -179,7 +179,7 @@
     </widget>
    </item>
    <item>
-    <widget class="QDialogButtonBox" name="buttonBox">
+    <widget class="QDialogButtonBox" name="_buttonBox">
      <property name="orientation">
       <enum>Qt::Horizontal</enum>
      </property>
@@ -203,7 +203,7 @@
  </resources>
  <connections>
   <connection>
-   <sender>buttonBox</sender>
+   <sender>_buttonBox</sender>
    <signal>accepted()</signal>
    <receiver>PinEntry</receiver>
    <slot>accept()</slot>
@@ -219,7 +219,7 @@
    </hints>
   </connection>
   <connection>
-   <sender>buttonBox</sender>
+   <sender>_buttonBox</sender>
    <signal>rejected()</signal>
    <receiver>PinEntry</receiver>
    <slot>reject()</slot>
diff --git a/src/smartcardauth.hxx b/src/smartcardauth.hxx
index 2a126be..a53b93e 100644
--- a/src/smartcardauth.hxx
+++ b/src/smartcardauth.hxx
@@ -208,7 +208,8 @@ class SmartCardAuth: public QObject {
                                             QSsl::Der), _parent);
           while (true) try {
               LOG<<"******************************************1*******";
-              pinEntry.retries(retries(c.slot->slotinfo().slotDescription));
+              pinEntry.tokeninfo(c.slot->tokeninfo())
+                .retries(retries(c.slot->slotinfo().slotDescription));
               LOG<<"******************************************2*******";
               int res(pinEntry.myexec());
               LOG<<"******************************************3*******";