GroupDocs.Signature for .NET 19.6 Release Notes

Major Features

There are about 15 new features, improvements and bug fixes in this regular release. Most features are related to support new image file format for most service methods, implementation of serialization and encryption of custom data objects into Metadata signatures for Image documents, with ability to extract them back and specify custom serialization and data encryption. Also this release contains some internal security improvements.

• Introduced ability to embed custom objects to Metadata Signature for Image Documents
• Improved and fixed digital signatures search
• Added page indicator for Signature object after search
• Implemented support of new image data formats for all service methods
• fixed some output file path issues for different save settings

Full List of Issues Covering all Changes in this Release

Public API and Backward Incompatible Changes

1. Public abstract class BaseSignature was extended with new property PageNumber to specify documentpage number where signature object was found over Search method.

   PageNumber property

   /// <summary>
   /// Specifies the page signature was found on  
   /// </summary>
   public int? PageNumber { get; }
   

   This field is supported for BarcodeSignature, QRCodeSignature and Pdf Digital Signature types. The rest signature types are not related to specific page but only to Document. This is true for Digital and Metadata Signatures.

   Following example demonstrates searching document for QRCode signature and display signatures with page numbers:

   // setup Signature configuration
   SignatureConfig signConfig = new SignatureConfig
   {
       StoragePath = @"c:\Aspose\Test\Storage",
       OutputPath = @"c:\Aspose\Test\Output"
   };
   // instantiating the signature handler
   SignatureHandler handler = new SignatureHandler(signConfig);
   // setup search options
   PdfSearchQRCodeOptions searchOptions = new PdfSearchQRCodeOptions();
   // specify as true to search all pages of a document
   searchOptions.SearchAllPages = true;
   // search document
   SearchResult result = handler.Search("SignedQRCode.pdf", searchOptions);
   // output signatures
   // output signatures
   List<QRCodeSignature> signatures = result.ToList<QRCodeSignature>();
   foreach (QRCodeSignature signature in signatures)
   {
       Console.WriteLine("Found QRCode signature: {0} with text {1} on page {2}", signature.EncodeType.TypeName, signature.Text, signature.PageNumber);
   }
   

2. Public class ImageMetadataSignOptions was extended with new public method AddSignature. Method creates new Image Metadata Signature with passed arguments (id and value), adds signature to list of metadata signatures and returns newly created object as result.

   AddSignature method

   /// <summary>
   /// Creates new ImageMetadataSignature with passed arguments and adds it to collection.
   /// </summary>
   /// <param name="id">Unique identifier Image Metadata Signature name. See references for Exif tags specifications for possible id values</param>
   /// <param name="value">Metadata value</param>
   /// <returns>Newly created signature that was added to MetadataSignatures collection</returns>
   public ImageMetadataSignature AddSignature(ushort id, object value)
   

   Following example demonstrates singing Image document with Metadata signature using this new method:

   // setup Signature configuration
   SignatureConfig signConfig = new SignatureConfig
   {
       StoragePath = @"c:\Aspose\Test\Storage",
       OutputPath = @"c:\Aspose\Test\Output"
   };
   // instantiating the signature handler
   SignatureHandler handler = new SignatureHandler(signConfig);
   // setup options with text of signature
   ImagesMetadataSignOptions signOptions = new ImagesMetadataSignOptions();
   // Specify different Metadata Signatures and add them to options sigature collection
   // set start id
   ushort imgsMetadataId = 41996;
   // setup int value
   ImageMetadataSignature mdSign_DocId = signOptions.AddSignature(imgsMetadataId++, 123456); // int
   // setup Author property
   ImageMetadataSignature mdSign_Author = signOptions.AddSignature(imgsMetadataId++, "Mr.Scherlock Holmes"); // string
   // setup data of sign date
   ImageMetadataSignature mdSign_Date = signOptions.AddSignature(imgsMetadataId++, DateTime.Now); // DateTime
   // setup double
   ImageMetadataSignature mdSign_Amnt = signOptions.AddSignature(imgsMetadataId++, 123.456M); //decimal value
   
   // sign document
   string signedPath = handler.Sign<string>(@"SignedMetadata.jpg", signOptions,
       new SaveOptions { OutputType = OutputType.String, OutputFileName = "SignedMetadata2.jpg" });
   Console.WriteLine("Signed file path is: " + signedPath);
   

3. Public base abstract class MetadataSignature, ImageMetadataSignature was extended with new public property DataEncryption of type IDataEncryption

   DataEncryption property

   /// <summary>
   /// Gets or sets implementation of <see cref="IDataEncryption"/> interface to encode and decode signature Value properties.
   /// </summary>
   public IDataEncryption DataEncryption { get; set; }
   

   and virtual method public T GetData(). This method returns object of type T over de-serialization and decryption from Metadata Value.

   GetData() method

   /// <summary>
   /// Obtain object from Metadata Signature Value over de-serialization and decryption
   /// </summary>
   /// <typeparam name="T">Type of object to deserialize from Metadata value</typeparam>
   /// <returns></returns>
   public T GetData<T>() where T : class
   
   /// <summary>
   /// Obtain object from Metadata Signature Value over deserialization.
   /// </summary>
   /// <typeparam name="T">Type of object to deserialize from Metadata Value</typeparam>
   /// <param name="dataEncryption">Set custom data encryption implementation</param>
   /// <returns></returns>
   public T GetData<T>(IDataEncryption dataEncryption) where T : class 
   

   With these changes all derived classes, same as ImageMetadataSignature will support this functionality.

   Following example demonstrates singing Image documents with Metadata signature with value of  DocumentSignature object:

   // setup key and passphrase
   string key = "1234567890";
   string salt = "1234567890";
   // create data encryption
   IDataEncryption encryption = new SymmetricEncryption(SymmetricAlgorithmType.Rijndael, key, salt);
   // setup Signature configuration
   SignatureConfig signConfig = new SignatureConfig
   {
       StoragePath = @"c:\Aspose\Test\Storage",
       OutputPath = @"c:\Aspose\Test\Output"
   };
   // instantiating the signature handler
   SignatureHandler handler = new SignatureHandler(signConfig);
   // setup options with text of signature
   ImagesMetadataSignOptions signOptions = new ImagesMetadataSignOptions();
   // create custom object
   DocumentSignature signature = new DocumentSignature()
   {
       ID = Guid.NewGuid().ToString(),
       Author = Environment.UserName,
       Signed = DateTime.Now,
       DataFactor = 11.22M
   };
   ushort imgsMetadataId = 41996;
   // Specify different Metadata Signatures and add them to options sigature collection
   // setup Author property
   ImageMetadataSignature mdDocument = signOptions.AddSignature(imgsMetadataId, signature);
   // set encryption
   mdDocument.DataEncryption = encryption;
   // sign document
   string signedPath = handler.Sign<string>(@"SignedMetadata.jpg", signOptions,
       new SaveOptions { OutputType = OutputType.String, OutputFileName = "SignedMedataDataEncrypted.jpg" });
   Console.WriteLine("Signed file path is: " + signedPath);
   

   Class DocumentSignature written by user

   Example of custom class

   public class DocumentSignature
   {
       // specify SkipSerialization attribute to skip this field on serialization
       [SkipSerialization]
       public string Version { get; set; }
       // specify SkipSerialization attribute to skip this field on serialization
       [SkipSerialization]
       public bool IsProcessed { get; set; }
       [Format("SignatureID")]
       public string ID { get; set; }
       [Format("Author")]
       public string Author { get; set; }
       [Format("SignatureDate","yyyy-MM-dd")]
       public DateTime Signed { get; set; }
       [Format("Factor", "N2")]
       public decimal DataFactor { get; set; }
   }
   

   Following example shows how to retrieve signed Cells file with DocumentSignature Metadata Value:

   // setup key and pasphrase
   string key = "1234567890";
   string salt = "1234567890";
   // create data encryption
   IDataEncryption encryption = new SymmetricEncryption(SymmetricAlgorithmType.Rijndael, key, salt);
   // setup Signature configuration
   SignatureConfig signConfig = new SignatureConfig
   {
       StoragePath = @"c:\Aspose\Test\Storage",
       OutputPath = @"c:\Aspose\Test\Output"
   };
   // instantiating the signature handler
   SignatureHandler handler = new SignatureHandler(signConfig);
   // setup search options
   CellsSearchMetadataOptions searchOptions = new CellsSearchMetadataOptions();
   // search document
   SearchResult result = handler.Search("SignedMedataDataEncrypted.xlsx", searchOptions);
   // output signatures
   List<CellsMetadataSignature> signatures = result.ToList<CellsMetadataSignature>();
   foreach (CellsMetadataSignature signature in signatures)
   {
       if (signature != null && signature.Name.Equals("DocumentSignature"))
       {
           DocumentSignature docSignature = signature.GetData<DocumentSignature>(encryption);
           if (docSignature != null)
           {
               Console.WriteLine("Found DocumentSignature signature: #{0}. Author {1} from {2}. Factor: {3}",
                   docSignature.ID, docSignature.Author, docSignature.DataFactor, docSignature.DataFactor);
           }
       }
   }
   

   Following example shows how to retrieve signed Image with DocumentSignature Metadata Value (see examples above how to sign Document with custom data objects):

   // setup key and pasphrase
   string key = "1234567890";
   string salt = "1234567890";
   // create data encryption
   IDataEncryption encryption = new SymmetricEncryption(SymmetricAlgorithmType.Rijndael, key, salt);
   // setup Signature configuration
   SignatureConfig signConfig = new SignatureConfig
   {
       StoragePath = @"c:\Aspose\Test\Storage",
       OutputPath = @"c:\Aspose\Test\Output"
   };
   // instantiating the signature handler
   SignatureHandler handler = new SignatureHandler(signConfig);
   // setup search options
   ImagesSearchMetadataOptions searchOptions = new ImagesSearchMetadataOptions();
   // search document
   SearchResult result = handler.Search("SignedMedataDataEncrypted.jpg", searchOptions);
   // output signatures
   List<ImageMetadataSignature> signatures = result.ToList<ImageMetadataSignature>();
   ushort imgsMetadataId = 41996;
   foreach (ImageMetadataSignature signature in signatures)
   {
       if (signature != null && signature.Id.Equals(imgsMetadataId))
       {
           DocumentSignature docSignature = signature.GetData<DocumentSignature>(encryption);
           if (docSignature != null)
           {
               Console.WriteLine("Found DocumentSignature signature: #{0}. Author {1} from {2}. Factor: {3}", 
                       docSignature.ID, docSignature.Author, docSignature.Signed.ToShortDateString(), docSignature.DataFactor);
           }
       }
   }