diff --git a/pom.xml b/pom.xml
index 38a4a03b..f7fe3f7e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -86,6 +86,11 @@
       <artifactId>dom4j</artifactId>
       <version>${dom4j.version}</version>
     </dependency>
+    <dependency>
+      <groupId>com.itextpdf</groupId>
+      <artifactId>itext-saslprep</artifactId>
+      <version>1.0.0</version>
+    </dependency>
     <dependency>
       <groupId>com.itextpdf</groupId>
       <artifactId>pdftest</artifactId>
diff --git a/src/main/java/com/itextpdf/rups/model/PdfFile.java b/src/main/java/com/itextpdf/rups/model/PdfFile.java
index 18ebfb21..2a44445e 100644
--- a/src/main/java/com/itextpdf/rups/model/PdfFile.java
+++ b/src/main/java/com/itextpdf/rups/model/PdfFile.java
@@ -48,6 +48,7 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.pdf.PdfReader;
 import com.itextpdf.kernel.pdf.PdfWriter;
 import com.itextpdf.kernel.pdf.ReaderProperties;
+import com.itextpdf.passwordprep.PdfPasswordUtil;
 
 import javax.swing.*;
 import java.io.*;
@@ -137,8 +138,8 @@ public void selectInitialValue() {
 
         pane.createDialog(null, "Enter the User or Owner Password of this PDF file").setVisible(true);
 
-        // TODO RES-427: SASLprep & truncate this
-        return new String(passwordField.getPassword()).getBytes(StandardCharsets.UTF_8);
+        String passwordString = new String(passwordField.getPassword());
+        return PdfPasswordUtil.preparePasswordForOpen(passwordString);
     }
 
     /**