--- title: "Sample code in C# for pattern redaction and highlighting | Nutrient DCS" canonical_url: "https://www.nutrient.io/guides/document-converter/document-converter-services/document-security/code-samples/" md_url: "https://www.nutrient.io/guides/document-converter/document-converter-services/document-security/code-samples.md" last_updated: "2026-06-09T10:25:14.368Z" description: "Implement pattern redaction, highlighting, and smart redaction using C# and Nutrient Document Converter Services. Complete code examples included." --- # Sample code in C# for pattern redaction and highlighting This guide provides C# code examples for implementing document security features using Nutrient Document Converter Services (DCS). Document security is essential for protecting sensitive information in various scenarios: - **Pattern redaction** - Permanently removes sensitive content like social security numbers, credit card numbers, or personal identifiable information - **Pattern highlighting** - Visually marks sensitive content without removing it, useful for review processes - **Smart redaction** - Uses intelligent algorithms to automatically identify and redact common sensitive data patterns Choose the appropriate method based on your security requirements and compliance needs. ## Prerequisites Before implementing document security features, ensure you have: - Nutrient Document Converter Services installed and running -.NET Framework or.NET Core development environment - Document files for testing security operations - Implemented `OpenService` and `CloseService` methods from the [`DocumentConverterServiceClient`](https://www.nutrient.io/guides/document-converter/document-converter-services/knowledge-base/open-and-close-documentconverterserviceclient/) sample code - Appropriate permissions for file system access ## Pattern redaction sample code ```csharp /// /// Perform Smart Redaction on the supplied file, writing the result into the target folder /// /// URL endpoint for the PDF Converter service /// Source filename /// Target folder to receive the output file static void SmartRedaction(string ServiceURL, string sourceFileName, string targetFolder) { DocumentConverterServiceClient client = null; try { // Create minimum OpenOptions object OpenOptions openOptions = new OpenOptions(); openOptions.OriginalFileName = Path.GetFileName(sourceFileName); // Create minimum SmartRedactionSettings SmartRedactionSettings smartRedactionSettings = new SmartRedactionSettings(); smartRedactionSettings = new SmartRedactionSettings(); // Set what needs to be redacted smartRedactionSettings.RedactCreditCardNumbers = BooleanEnum.True; smartRedactionSettings.RedactEmailAddresses = BooleanEnum.True; smartRedactionSettings.RedactPhoneNumbers = BooleanEnum.True; // Create target folder if required if (!Directory.Exists(targetFolder)) { Directory.CreateDirectory(targetFolder); } // ** Read the source file into a byte array. byte[] sourceFile = File.ReadAllBytes(sourceFileName); // ** Open the service and configure the bindings client = OpenService(ServiceURL); // ** Carry out the conversion. byte[] result = client.SmartRedaction(sourceFile, openOptions, smartRedactionSettings); // ** Save the results if (result!= null) { if (!Directory.Exists(targetFolder)) { Directory.CreateDirectory(targetFolder); } string filename = Path.GetFileNameWithoutExtension(sourceFileName); string destinationFileName = Path.GetFullPath(Path.Combine(targetFolder, filename + "-redacted.pdf")); using (FileStream fs = File.Create(destinationFileName)) { fs.Write(result, 0, result.Length); fs.Close(); } Console.WriteLine("File converted to " + destinationFileName); } else { Console.WriteLine("Nothing returned"); } } catch (FaultException ex) { Console.WriteLine($"FaultException occurred: ExceptionType: {ex.Detail.ExceptionType.ToString()}"); Console.WriteLine(); Console.WriteLine($"Error Detail: {string.Join(Environment.NewLine, ex.Detail.ExceptionDetails)}"); Console.WriteLine($"Error message: {ex.Message}"); Console.WriteLine(); Console.WriteLine($"Error reason: {ex.Reason}"); } catch (Exception ex) { Console.WriteLine(ex.Message); Console.WriteLine(ex.StackTrace); Console.WriteLine(ex.Data.ToString()); } finally { if (client!= null) { CloseService(client); } } } ``` ## Pattern highlighting sample code Pattern highlighting identifies specific patterns in a document and visually highlights them without removing the underlying content. This example shows how to implement pattern highlighting using the API: ```csharp /// /// Perform pattern redaction on the supplied file, writing the result into the target folder. /// /// URL endpoint for the PDF Converter service. /// Source filename. /// Target folder to receive the output file. static void PatternRedaction(string ServiceURL, string sourceFileName, string targetFolder) { DocumentConverterServiceClient client = null; try { // Create minimum `OpenOptions` object. OpenOptions openOptions = new OpenOptions(); openOptions.OriginalFileName = Path.GetFileName(sourceFileName); // Create minimum `PatternHighlightSettings`. PatternHighlightSettings patternHighlightSettings = new PatternHighlightSettings(); // Set the highlight color. patternHighlightSettings.Red = 0; patternHighlightSettings.Green = 0; patternHighlightSettings.Blue = 255; patternHighlightSettings.Alpha = 255; patternHighlightSettings.Pattern = "\"374245455400126\""; // Create target folder if required. if (!Directory.Exists(targetFolder)) { Directory.CreateDirectory(targetFolder); } // ** Read the source file into a byte array. byte[] sourceFile = File.ReadAllBytes(sourceFileName); // ** Open the service and configure the bindings. client = OpenService(ServiceURL); // ** Carry out the highlighting. byte[] result = client.PatternHighlight(sourceFile, openOptions, patternHighlightSettings); // ** Save the results. if (result!= null) { if (!Directory.Exists(targetFolder)) { Directory.CreateDirectory(targetFolder); } string filename = Path.GetFileNameWithoutExtension(sourceFileName); string destinationFileName = Path.GetFullPath(Path.Combine(targetFolder, filename + "-highlighted.pdf")); using (FileStream fs = File.Create(destinationFileName)) { fs.Write(result, 0, result.Length); fs.Close(); } Console.WriteLine("File converted to " + destinationFileName); // Open the destination file. ProcessStartInfo psi = new ProcessStartInfo(); psi.FileName = destinationFileName; psi.UseShellExecute = true; Process.Start(psi); } else { Console.WriteLine("Nothing returned"); } } catch (FaultException ex) { Console.WriteLine($"FaultException occurred: ExceptionType: {ex.Detail.ExceptionType.ToString()}"); Console.WriteLine(); Console.WriteLine($"Error Detail: {string.Join(Environment.NewLine, ex.Detail.ExceptionDetails)}"); Console.WriteLine($"Error message: {ex.Message}"); Console.WriteLine(); Console.WriteLine($"Error reason: {ex.Reason}"); } catch (Exception ex) { Console.WriteLine(ex.Message); Console.WriteLine(ex.StackTrace); Console.WriteLine(ex.Data.ToString()); } finally { if (client!= null) { CloseService(client); } } } ``` ## Smart redaction sample code ```csharp /// /// Perform Smart Redaction on the supplied file, writing the result into the target folder /// /// URL endpoint for the PDF Converter service /// Source filename /// Target folder to receive the output file static void SmartRedaction(string ServiceURL, string sourceFileName, string targetFolder) { DocumentConverterServiceClient client = null; try { // Create minimum OpenOptions object OpenOptions openOptions = new OpenOptions(); openOptions.OriginalFileName = Path.GetFileName(sourceFileName); // Create minimum SmartRedactionSettings SmartRedactionSettings smartRedactionSettings = new SmartRedactionSettings(); smartRedactionSettings = new SmartRedactionSettings(); // Set what needs to be redacted smartRedactionSettings.RedactCreditCardNumbers = BooleanEnum.True; smartRedactionSettings.RedactEmailAddresses = BooleanEnum.True; smartRedactionSettings.RedactPhoneNumbers = BooleanEnum.True; // Create target folder if required if (!Directory.Exists(targetFolder)) { Directory.CreateDirectory(targetFolder); } // ** Read the source file into a byte array. byte[] sourceFile = File.ReadAllBytes(sourceFileName); // ** Open the service and configure the bindings client = OpenService(ServiceURL); // ** Carry out the conversion. byte[] result = client.SmartRedaction(sourceFile, openOptions, smartRedactionSettings); // ** Save the results if (result!= null) { if (!Directory.Exists(targetFolder)) { Directory.CreateDirectory(targetFolder); } string filename = Path.GetFileNameWithoutExtension(sourceFileName); string destinationFileName = Path.GetFullPath(Path.Combine(targetFolder, filename + "-redacted.pdf")); using (FileStream fs = File.Create(destinationFileName)) { fs.Write(result, 0, result.Length); fs.Close(); } Console.WriteLine("File converted to " + destinationFileName); } else { Console.WriteLine("Nothing returned"); } } catch (FaultException ex) { Console.WriteLine($"FaultException occurred: ExceptionType: {ex.Detail.ExceptionType.ToString()}"); Console.WriteLine(); Console.WriteLine($"Error Detail: {string.Join(Environment.NewLine, ex.Detail.ExceptionDetails)}"); Console.WriteLine($"Error message: {ex.Message}"); Console.WriteLine(); Console.WriteLine($"Error reason: {ex.Reason}"); } catch (Exception ex) { Console.WriteLine(ex.Message); Console.WriteLine(ex.StackTrace); Console.WriteLine(ex.Data.ToString()); } finally { if (client!= null) { CloseService(client); } } } ``` ## Troubleshooting **Pattern matching error: Pattern not found** - Verify that the pattern exists in the document - Check pattern syntax and escape special characters - Ensure the pattern format matches the document content structure **Security operation error: Permission denied** - Verify that the application has read access to source documents - Check that the output directory has write permissions - Ensure documents aren’t password-protected or locked by other applications **Service connection error: Cannot connect to DCS** - Ensure Nutrient Document Converter Services is running and accessible - Verify the service URL in your code matches your DCS installation - Check that no firewall is blocking the connection **Performance issues: Slow processing** - Consider processing documents in batches for large volumes - Optimize pattern complexity to reduce processing time - Monitor memory usage for large documents ## What’s next Now that you understand document security implementation with C#, explore these related capabilities: - **Python implementation** - Compare with [pattern redaction using Python](https://www.nutrient.io/guides/document-converter/document-converter-services/document-security/pattern-redaction-using-python.md) for cross-language insights - **Complete C# guide** - Review the [document security with C#](https://www.nutrient.io/guides/document-converter/document-converter-services/document-security/csharp.md) guide for more features --- ## Related pages - [Secure PDF API](/guides/document-converter/document-converter-services/document-security.md) - [Secure PDF and MS Office documents with Java](/guides/document-converter/document-converter-services/document-security/java.md) - [Secure and protect PDFs and Office documents in C#](/guides/document-converter/document-converter-services/document-security/csharp.md) - [Secure your PDFs and Office files easily with .NET](/guides/document-converter/document-converter-services/document-security/dotnet-core.md) - [WSDL URL.](/guides/document-converter/document-converter-services/document-security/pattern-redaction-using-python.md) - [WSDL URL.](/guides/document-converter/document-converter-services/document-security/pattern-highlighting-using-python.md) - [Secure PDF and Office documents with JavaScript](/guides/document-converter/document-converter-services/document-security/javascript.md) - [Pattern redaction and highlighting with C#](/guides/document-converter/document-converter-services/document-security/pattern-redaction-and-highlighting.md) - [Password protection for PDF documents in PHP](/guides/document-converter/document-converter-services/document-security/php.md) - [Smart document redaction with C#](/guides/document-converter/document-converter-services/document-security/smart-redaction.md)