diff --git a/src/PdfSharp/Pdf.Internal/PdfEncoders.cs b/src/PdfSharp/Pdf.Internal/PdfEncoders.cs
index 661d4dc6..a2fb9195 100644
--- a/src/PdfSharp/Pdf.Internal/PdfEncoders.cs
+++ b/src/PdfSharp/Pdf.Internal/PdfEncoders.cs
@@ -398,6 +398,7 @@ public static byte[] FormatStringLiteral(byte[] bytes, bool unicode, bool prefix
                 }
                 else
                 {
+                    securityHandler?.EncryptBytes(bytes);
                     pdf.Append('<');
                     for (int idx = 0; idx < count; idx++)
                         pdf.AppendFormat("{0:X2}", bytes[idx]);